What are the "sexual causes" for the French Revolution cited in Wikipedia?

I tried to do what research that I could. I found there was actually a fairly active role for women in the French Revolution, many of them hoping (in vain) for improved political and social status. However, as mentioned by another user in the comments, France was (and despite the best efforts of the Jacobins, remained) a very Catholic country. Plural marriages there were not performed.

I did find something though. There have been recent (14 years ago) riots in France, that some folks have blamed on polygamy. That's an argument that IMHO shows some very weak (and directed) reasoning, but I daresay its perhaps the same kind of weak reasoning that might make that same person confuse those riots with The French Revolution.

So my guess is that your anonymous poster heard someone talking about polygamy being behind those riots, perhaps their English (or French) isn't great, and they thought that WP page was about the same thing.

Riot / Revolution, honest mistake, right?

They may have had in mind the "right of the first night" Droit du seigneur. It does not really matter whether this "right" really existed or not and how frequently it was practiced. But it was used in pre-revolutionary propaganda against the old regime as the comedy by Beaumarchais " La Folle journée ou Le Mariage de Figaro" (1778) shows.

Q: “Sexual causes” for the French Revolution?

Ouh, oui!
Sexual mores, or simply biopolitics or biopower did play a role.

Morals, social norms and social problems related to sex and gender roles: like the overall relation between men and women, especially divorce, remarrying, polygamy, and how they were regulated. What that meant for population numbers, social security and welfare, inheritances and legitimacy of offspring. How the elites behaved and state, nobility and church enforced their moral arguments—against enlightenment discourses—were substantial issues leading up to and during the revolution.

[…] another powerful concept imbued with ultimate moral prestige in eighteenth-century France: populationism. Reproaching the King of France and the Catholic Church for depopulating the nation became an immensely effective arm in the battles of the Enlightenment. A large corpus of works proclaimed there was no higher purpose than to further national demographic progress by any means—including the adoption of new models of sexual behavior.

[…] famous texts, such as the celebrated “depopulation letters” of Montesquieu’s Lettres persanes and Diderot’s audacious Supplément au voyage de Bougainville, […] a large quantity of lesser-known writings, many of which nevertheless exercised great influence in their time. In these works are formulated projects for increasing France’s population by means of manipulating and regulating sexual relations between men and women within the context of one overriding priority, encouraging the birthrate. These texts urge such programs as the reduction or even interdiction of celibacy, the legalization of divorce, the introduction of polygamy, and the elimination of a whole variety of ecclesiastical and legal sexual taboos, even those against violence and incest. Thus a purportedly objective referent, the numerical representation of the nation’s population, became the vehicle for a wide-ranging critique of the most intimate details of the citizens’ lives as well as a powerful weapon in the Enlightenment’s battles against the monarchy and the Church. (Blum)

What the passage about "polygamy" may allude to is actually not that France was 'suffering' from widespread polygamy.

In fact it was the opposite!

If you want to find factors prior to the French revolution that in part fomented it, then the idea and want for polygamy, loosened sexual mores! Many public intellectuals wanted polygamy. A status of sex/gender affairs that was known not only from Muslim lands, but of course also seen within France. But 'naturally', not among the Catholic lower and middle classes. But the male aristocracy was well known for using the services of quite a substantial number of mistresses, thus already practicing polygamy.

The opposite side is also true. Moralistic and Christian opposition to either the aristocratic behaviour, the behaviour found in Paris streets and the 'funny ideas' of intellectuals were a factor that just increased the overall tension, above the attitude of "the aristocrats", like exemplified in another matter but same mood: la Grande Peur.

One example for this opposite aspect would be the Affair of the Diamond Necklace.

But the sexual mores of the time and place were indeed a contested issue. The elite violating the morals handed down by clerical institutions, the urban situation regarding the same, intellectual arguments pro polygamy (as well as against)—with corresponding opposition against aristocracy and clerical circles, for most explicitly conflicting reasons regarding both were certainly not sedative.

That was the situation largely described now for polygamy in the modern sense of polyamory a term not available at the time. A part of that may be better called libertine:

one devoid of most moral principles, a sense of responsibility, or sexual restraints, which are seen as unnecessary or undesirable, especially one who ignores or even spurns accepted morals and forms of behaviour sanctified by the larger society.

Catholic discourse stretched polygamy even out fully to encompass re-marrying as (serial-) polygamy, a thing the moralists and clerics found particularly unsuited for women, based on a strict reading of 1 Cor 7, 8–10.

The very term 'polygamy' has also be dissected further. It was/is different from bigamy as the first describes the custom and the latter the canonical legal offense.

Relationships that were described as fornication or adultery might turn into marriages if circumstances permitted. They might reflect some types of courting behavior, and talk of eventual marriage did occasionally find its way into the testimony connected with such cases. As for bigamy cases, each describes the beginning of at least one marriage. Priestly concubinage, on the other hand, always involved a person who was not permitted to marry under any circumstances. It is conceivable that some priests and their concubines regarded themselves as married in the sight of God, but the courts would not as a rule allow anything like that to be mentioned. Divorce was really separation; it concerned the end of a marriage but an end not so final as to permit either partner to remarry.
–– André Burguière: "Family and Sexuality in French History",University of Pennsylvania Press, 1980.

So the whole spectrum was observed: from loosened morals and 'free love', over legalised institutional polygamy to tightened morals like forbidding celibacy – all positions were argued for and against shortly prior and during the revolution. Whether from moral angles or population politics, pleasure or inheritance questions. Men's rights or women's non-rights (an exaggeration, only slightly). 'Polygamy' was one quite important aspect in that, but as the heading for that whole category – as pars pro toto – it may be not the best fit.

It seems necessary to mention yet another one exemplar of revolutionary politician of whose interests Wikipedia summarises

Main interests: Pornography, eroticism, politics

Needless to say that his name was Donatien Alphonse François, Marquis de Sade. His Philosophy in the Bedroom may be published a bit late for a trigger cause, but certainly not for he events unfolding:

[…] the only moral system that reinforces the recent political revolution is libertinism, and that if the people of France fail to adopt the libertine philosophy, France will be destined to return to a monarchic state. […] there is a lengthy section where the character Chevalier reads a philosophical pamphlet titled "Frenchmen, Some More Effort If You Wish To Become Republicans". The pamphlet clearly represents Sade's philosophy on religion and morality, a philosophy he passionately hopes the citizens of France will embrace and codify into the laws of their new republican government.

Certainement un homme aura plus d’enfants avec vingt femmes qu’avec une seule. André-Pierre le Guay de Prémontval, La Monogamie, 1751

In these works are formulated projects for increasing France’s population by means of manipulating and regulating sexual relations between men and women within the context of one overriding priority, encouraging the birthrate. These texts urge such programs as the reduction or even interdiction of celibacy, the legalization of divorce, the introduction of polygamy, and the elimination of a whole variety of ecclesiastical and legal sexual taboos, even those against violence and incest.

Montesquieu’s conclusion points in the direction that many eighteenth- century thinkers will follow, attempting by numerous means to improve the well-being of France’s citizenry. The following chapters explore the abundant consequences of his other populationist ideas: the effect of celibacy, the demographic disadvantages of indissoluble marriage, the connection between polygamy and population, alternate forms of sexual union, and, finally, the emergence of a new recipe for fruitful marriage.

Widows presented a special problematic case, since an ancient traditional prejudice against remarriage was coupled with a Catholic insistence on the marriage sacrament as an eternal bond, discouraging what was referred to as “serial polygamy.”

In their efforts to disestablish Catholic marriage, however, while at the same time debating legislation to eliminate the stigma of illegitimacy (eventual law of 12 brumaire an II), the Revolutionaries found themselves faced with the possibility of a kind of de facto polygamy after all. In Oudot’s Essai, he proposed two forms of State-recognized marriage: one to be “solemn,” the other “private.” While article 8 of his projected law stated that polygamy would be forbidden, by permitting a man as many “private” marriages as he wished, a system of informal polygamy would in effect be established. Oudot recognized the contradiction but commented philosophically that the “law ought not forbid what it cannot prevent … since other unions exist, independent of the law, how can the law not recognize the results and how can it refuse to protect the children that are the consequences?”. Oudot’s plan was of course not accepted, but the possibilities that he raised continued to be treated seriously by various citizens from time to time during the period of the Convention.

Although some commentators claimed the permissive divorce law of 1792 legalized “serial” polygamy, simultaneous polygamy was basically not on the legislative agenda. The rhetorical enthusiasm that had been expressed over this “primitive right of man” prior to the Revolution nonetheless made its way to the floor of the Assembly in other guises.

Since the law supposedly protects natural children, says Fleurant, “polygamy will solve the problem of illegitimacy.”

Mary Wollstonecraft, like Saint Just, favored the legalization of a kind of polygamy in 1792, insisting that the practice “is drawn from the well-attested fact, that in the countries where it is established, more females are born than males.”
–– Carol Blum: "Strength in Numbers. Population, Reproduction, and Power in Eighteenth-Century France", The Johns Hopkins University Press: Baltimore & London, 2002.
Especially chapter 5: Polygamy: Fertility and the Lost Right of Man.

That "polygamy, yes or no" was an issue prominent prior to and during the revolution is of course not an excuse for Wikipedia to not include sources. Also, the sentence that "Men used to force women despite their will" seems a little disconnected from the rest. Strictly speaking, this is almost exclusively rape, or forced marriage; if not a bit too generically about "the patriarcal system". Both being not really covered by the conscept of 'polygamy'?

Six months later, having read the Vie privee du Vicomte de Mirabeau, he speaks of it and the memoirs of Bezenval as "the most valuable documents relating to that moral condition of France out of which the Revolution arose."

Mackintosh also reacted strongly to the memoirs of Mme. Roland and the letters of Mile, de Lespinasse in 1811. He transcribed parts of the memoirs of Mme. de Montespan, which he read in 1820, taking immense care in recording them. After the death of Mme. de Stael, her son Auguste wrote to ask Mackintosh for help in publishing her book on the Revolution (the Considerations), commenting on the de­ based eagerness with which the English public swallowed biographies, anecdotes, and other material on the private lives of public figures. Mackintosh is by implication innocent of this charge. He read this material for its historical interest, for an account of what he called the "moral condition" of France before the Revolution, and came to the conclusion that it was the very sexual license, begun under the Re­gency, which so sapped the French character that it became vulnerable to the infection of dangerous ideas. Others […] were willing to treat this licentiousness as a national characteristic of the French; but Mackintosh saw it as a historical fact of the French eighteenth century. He was nonetheless horrified by it.

The letters of Julie de Lespinasse, one of the great hostesses of the Enlightenment salons of Paris, impressed him with their eloquence on the subject of love. But since the love described was adulterous, Mackintosh wished that they had been written by a man, since for a woman to write so "is such an outrage upon our Sentiments that it is difficult for us to consider it dispassionately." He goes on:

If I were to value myself upon any thing it would be upon having better showed than other moralists the immense importance of female purity & its tendency to produce every other virtue…
However justly we may reprobate the Parisian morals every individual at Paris must be tried by a reference to that standard. It is almost as unreasonable… to blame a Parisian Lady in the eighteenth century for offending against the rules of purity as it would be to think ill of a Mahometan for Polygamy.

The next day he recorded in his journal the opinion that "the Palace of Louis XV was for forty years a brothel. Licentiousness in this trium­phant State easily found immoral theory."

So there it is in a nutshell. Like the other "high Protestant alarmists for social order in England," Mackintosh was convinced that sexual purity was a necessary condition for the attainment of liberty. This was the reason for the French failure after 1789. Lasciviousness denied liberty; French society had become decadent, and the Revolution was the culmination of that decay, not a recuperation from it.
–– Seamus Deane: "The French Revolution and Enlightenment in England, 1789–1832", Harvard University Press, 1988.

An historian writer at the time is of peculiar interest:

In the Moeurs et Coutumes, Le Gendre began as far back in time as possible, and described the earliest French people as "demi-sauvages," living off roots, fruits, and the product of the chase. He portrayed their homes made of wood, their pre-Christian mythological gods, their concern with hospitality, their barter economy, their armaments, their political and religious officials, their socially unequal judicial system.

He then mentioned the power of the king over the laws, but since royal supremacy was not his primary focus, he continued with a description of medieval trial procedures, which he viewed as the remnant of a barbarous paganism. Further examples of barbarism existed, according to Le Gendre, in practices of divorce, incest, and polygamy, evident even at the court of Charlemagne.
–– Phyllis K. Leffler: "French Historians and the Challenge to Louis XIV's Absolutism", French Historical Studies, Vol. 14, No. 1, 1985, pp. 1-22.
[Louis Le Gendre: "Nouvelle histoire de France, depuis le commencement de la monarchie, jusques a la mort de Louis XIII", 3 vols, (Paris, 1718), I, [vii]. The Moeurs et Coutumes was first published separately in 1712 and later appended to the Nouvelle Histoire de France of 1718.]

Compared to

In L’orateur, he indicted both Mably for condemning deists to persecution in On Legislation (1776) and Rousseau for insisting in the Social Contract that atheists could be banished from the republic as lacking the ‘sentiments of sociability’ necessary to be a ‘good citizen and loyal subject’. For Cloots, ‘to drive out intolerants is itself the most absurd of intolerances’. Cloots stressed that the universal republic, unlike former colonial projects, would support religious pluralism: ‘may every man cultivate his field in his own manner; may every man practise the cult that he pleases; the general law will protect all cults and all cultures’. Yet there were limits: ‘all that does not harm society shall have free rein’. Polygamy was out: ‘would nine free men devote themselves to celibacy, to castration, to let one sole man languish with ten unhappy women?’. Cloots recognised that the universal establishment of the Declaration of the Rights of Man and Citizen came with a social program* that is, reforming ‘barbarous institutions’. He believed that this civilising project would be effected through enlightenment and example: ‘Difference in habits does not impede man from feeling or being capable of feeling the same sensations everywhere’.
–– Alexander Bevilacqua: "Conceiving the Republic of Mankind: The Political Thought of Anacharsis Cloots", History of European Ideas 38:4, 550-569, 2012.

A few books and Wikipedia need updating?

The subject of women-and the sexual politics of the revolutionary era –have been slow to inform general treatments of the French Revolutionary era. In the new overview works, as in the old, women and gender issues remain strangely absent, as for example, in François Furet and Mona Ozouf's massive Dictionnaire critique de la Revolution française or Donald Sutherland's France 1789–1815: Revolution and Counterrevolution.'

These works reflect the impact of questions raised by the study of women's history and by feminist scholarship during the last twenty years. These questions have culminated in redirecting historians' attention to the centrality of gender (the sociopolitical construction of the sexes) in human organization, a factor that, once rendered visible, deepens and enriches our understanding of the operations of power and authority as well as attempts to contest and redirect these operations through word and deed.
–– Karen Offen: "The New Sexual Politics of French Revolutionary Historiography", French Historical Studies, Vol. 16, No. 4, 1990.

Just look at the list of priorities in this instance:

Napoleon, contrary to the recommendations of jurists like Portalis who advocated for the retention of some cultural autonomy for minorities specifically concerning divorce, refused to tolerate this ambiguity and required unequivocal ideological conformity. Under the guise of harmonising Jewish law to French law he convened an ‘Assembly of Notables.’ Their task was to answer twelve questions regarding the compatibility of Jewish law with the law of the empire. The issue of divorce figured prominently as the second question on the list, after polygamy, and before the question on interfaith marriage.
–– Suzette Blom: "Jews, Divorce and the French Revolution", Eras, Edition 12, Issue 1, December 2010.

Polygamy on first spot of the list!

Ursula Vogel: "Political Philosophers And The Trouble With Polygamy: Patriarchal Reasoning In Modern Natural Law", History of Political Thought, V12, N2, 1991. p229–251.

One eminent philosopher was Montesqiue who coded his thoughts in his Lettres persanes, published anonymously from Amsterdam, to avoid upsetting opponents to such ideas.

Mary McAlpin: "Between Men for All Eternity: Feminocentrism in Montesquieu's Lettres persanes", Eighteenth-Century Life (2000) 24 (1): 45-61.

The other side

A work coming to the defense of traditional marriage, La Monogamie, was published in 1751 by the well-known mathematician André-Pierre Le Guay de Prémontval (1716–1764) with a preface by his wife, also a mathematician, Madame Pigeon de Prémontval (1724–1767). La Monogamie began with an attack on the alarming popularity of Polygamia triumphatrix: “To succeed these days,” the author charged, “it takes, in four words: frivolity, obscenity, impiety and malice, these are the characteristics of our century”
(Blum)

For Catholic France it was Tametsi, the doctrine of the Council of Trent in 1563, that definitively anathematized polygamy.

Although France never officially accepted Trent as binding on French Catholics, Tridentine strictures on marriage were incorporated into the Edict of Blois of 1580 and effectively interdicted polygamy in France both in faith and in law.

The informal plurality of households and acceptance of bastards that had been permissible in pre-Tridentine France became increasingly problematic after the Reformation, and by the eighteenth century concubinage, even that of the king, was officially not tolerated by the Church. The struggle to keep the reigning monarch to the discipline of monogamy took place over generations of French kings and was only successful with Louis XVI. In the Esprit des lois, Montesquieu, following Tacitus, explained that the Frankish kings and a few nobles had had more than one wife not out of lust but to demonstrate their superior social status: “These marriages were less a sign of incontinence than an attribute of dignity” (2:550).

The expansive sexuality of the late Bourbon kings, save the last, suggested vestiges of the old royal polygamous privilege, motivated, however, perhaps less by dignity than by incontinence. Nevertheless, royal adultery was denounced as mortal sin, even more blameworthy than for other men because of the scandal it displayed to the faithful. Louis XIV’s efforts to ensure the continuation of the Bourbon line by placing his legitimized bastard sons, the dukes of Maine and Toulouse, in the line of succession to the throne after his legitimate heir, the duke of Anjou, demonstrates how imperfectly Louis XIV accepted the Church’s limitations on his procreative prerogatives. The comte de Boulainvilliers argued in 1728 that tradition permitted such promotions to the royal line, listing many examples of royal bastards from the ninth-century Arnould, king of Eastern France and Germany, up through William the Conqueror who were not excluded from the throne. As Boulainvilliers pointed out, the line between monogamy and the quasipolygamous status of the king’s concubines was not firmly drawn until Henri IV suppressed the claims to nobility of illegitimate offspring.

Alongside what Flandrin has called the Stoico-Christian doctrine of marriage prevailing in France after Trent, a certain tradition of Gallic humanism that found polygamy congenial continued to surface in freethinking authors of the seventeenth and eighteenth centuries as well as at Versailles. Pierre Charron, whose approval of celibacy and of divorce were examined earlier, pointed out the disadvantages of Catholic monogamy:

According to the strictest Christianity, marriage is held in tight check. The only easy part is getting in. Other nations and other religions that tolerate and practice polygamy and repudiation [enjoy] the liberty to take women and leave them, in order to make marriage easier, freer and more fertile. [They] accuse Christianity of having … prejudiced friendship and multiplication, the principle aims of marriage, in as much as friendship is the enemy of all constraint & maintains itself better in honest liberty. One can see how much polygamy profits multiplication among the nations practicing it, the Jews, the Muhammadans and other barbarians piled up masses of four hundred thousand in battle.

Population, however, was not central to Charron’s thought, it was merely one more stone to throw at the institution of Christian marriage, in which the disabused Canon of the cathedral of Condom found so much to reproach. The point was taken, however, that the rigorous ideal of Christian monogamy was out of touch with reality in a way that mating customs in other religions were not. More realistic in their knowledge of men’s needs, unhampered by the illusory symmetry of one husband, one wife, “barbarians” produced more men to be deployed in battle than did Christians, demonstrating their superior grasp of Realpolitik.

As recored in:

QUARANTE-TROISIÈME ANNEXE (1) A LA SÉANCE DE LA CONVENTION NATIONALE DU LUNDI 24 JUIN 1793.
Préliminaires et ordre de la discussion sur la Constitution, proposés par J.-B. Harmand, député du département de la Meuse (2). (translated)

Then I would like the following provisions to be added to chapter ni, de Pétât des citoyens, which would form a fourth article: because finally, the state of citizens is not only limited to negative or positive faculties, there are still relative faculties, and these are perhaps the most essential; such are marriage, divorce, celibacy, polygamy, etc.

"Marriage is a purely civil contract, dissolvable by the consent of the parties or by the claim of one of them, in the cases and in the forms indicated by civil laws.

The French Constitution allows divorce and defends polygamy or the plurality of women.

It prohibits public vows of chastity or celibacy. »

A similar topic, this time including the violent men forcing 'consent' for marriage enters as well:

QUINZIÈME ANNEXE (2) a la seance de la convention nationale duvendredi 9 aout 1793.
Essai sur les principes de la législation des mariages privés et solennels, du divorce et de l'adoption qui peuvent être déclarés à la suite de l'Acte constitutionnel, par O.-F, Oudot, député de la Côte-d'Or:

Thus, those who use violence to obtain the necessary consent for marriage or who use seduction towards those who have not reached full puberty age, must be punished. […]

If a man can care for the children of several women, it seems that nothing should prevent him from making as many commitments as he can fulfill, but if we consider that the number of women does not exceed that of men, it is obvious that if the law allowed several women, it would necessarily force many citizens to celibacy or to live in disorder, and society cannot allow this source of inequality and disorder.

On the other hand, if the tenderness of fathers towards their children depends on the fidelity with which wives keep the conjugal faith, the interest of morals, reason and equity require that men set the example first.

It may be argued that by recognizing that it is in society's interest to outlaw polygamy, my system would introduce its use by considering all private and clandestine unions as marriages.

My answer is that the law must not defend what it cannot prevent: if the legislator recognizes that it is not beneficial to society for a man to have several wives, he did his duty when he said that the law would not sanction the union of a married man with a second woman until the first marriage had been destroyed by divorce.

But since there are other marriages that are independent of the law, can he refrain from recognizing their effects and refuse to protect the children who are the result?

Public honesty, morals, these are the objections of my opponents; but it seems that they only want the appearance and not the reality; they respect the forms and ignore nature's obligations. I am calling for the fulfilment of these sacred obligations; my principles are therefore more stringent than theirs. What morality is there in social institutions that constantly thwart nature's wishes,…

(via: https://frda.stanford.edu)

Further reading for social/sexual mores, gender-issue and population discourse:

– Rachel Fuchs: "France in Comparative Perspective’, in: Elinor Accampo, Rachel Fuchs & Mary Lynn Stewart (eds): "Gender and the Politics of Social Reform in France, 1870–1914", Baltimore, 1995.

– Sean M. Quinlan: "The Great Nation in Decline Sex, Modernity and Health Crises in Revolutionary France c.1750–1850", The History of Medicine in Context, Ashgate: Aldershot, 2007.

– Robert A. Nye: "Biology, Sexuality, and Morality in Eighteenth-Century France", Eighteeth-Century Studies 35, 2002.

–– John McManners: "Church and Society in Eighteenth-Century France: Volume 1: The Clerical Establishment and Its Social Ramifications", "Volume 2: The Religion of the People and the Politics of Religion", Oxford University Press: Oxford, New York, 1998.
(esp V1, p23, 71–73, 165, 615; V2: p266: "Antoine Arnauld went further, holding Aquinas to be mistaken – by natural law, interest was reasonable, and it stood condemned only because a certain tradition of biblical interpretation had been imposed by the magistracy of the Church. He drew a parallel with polygamy. A reasonable case can be argued for it, and if we accepted it, the conversion of the heathen would be facilitated; even so, since the Bible and the Church condemn it, we must do so also."