Did Napoleon ever say «On s'engage et puis… on voit»?

Bernard Cornwell claims it was Napoleon, that was Napoleon's style also, so it is believable. He would make quick and simple assertions like this, usually a way to start an argument he could win with an example from his campaigns.

According to French newspaper, Le Figaro, Napoléon never said that. You can follow this link to check it. A french Author, Julien Gracq, quoted it as Napoleon's tactics in "Un balcon en forêt" (source), and that might be all you can learn in French about that peculiar subject.

It seems very plausible to attach his quip to Lenin, as the Red October and its aftermath was practically exactly that: take action and see what comes out of it.

It seems very strange to attribute this 'motto' to Napoleon who is often portrayed as far more into planning and strategy and tactics. Well, for most of his career. The beginnings might be a little more like that. And equally coming back from Elba for 100 days also bears a certain resemblance for a fitting description. But then, quotes of spoken words from non-writing military are frequently embellished interpolations, or pure inventions anyway.

Lenin himself wrote exactly this:

Napoleon, I think, wrote: "On s'engage et puis ... on voit." rendered freely this means: "First engage in a serious battle and then see what happens." Well, we did first engage in a serious battle in October 1917, and then saw such details of development (from the standpoint of world history they were certainly details) as the Brest peace, the New Economic Policy, and so forth. And now there can be no doubt that in the main we have been victorious.

Who invented this saying is therefore clearly not Lenin, though very well he may have quoted this on occasion.

But another contender for invention is Yakov Petrovich Kulnev, Russian General famous from the Russo-Turkish-War onwards for extreme bravery:

In numerous publications of the first half of the 19th century he is credited with formulating this saying.

So by
Georg Wilhelm von Valentini: "Die Lehre vom Krieg: Der Türkenkrieg, Band 3" (Prussian General Staff), Boicke, 1822. (Quoting the phrase from the prior first volume p 309).

From him comes the practical saying (First volume S 309

on s'engage partout, et puis l'on voit!

Apparently this characteristic was repeated during the battle of Battin at the Danube on September 7 during the Campaign of 1809/10.

(Fulltext in French translation: Traité sur la guerre contre les Turcs. Tr. par L. Blesson, in English: Military reflections on Turkey. Extr. and tr. from the treatise on the art of war. By a military ...(seems incomplete))

'On s'engage partout, et puis l'on voit' appears in Literarisches Wochenblatt, Volume 3 - but not attrbuted to Napoleon, though he is twice mentioned in the short article. So we are now back to 1819, in Napoleon's lifetime. Perhaps this is a proverb rather than a quotation?

The attribution certainly predates Lenin. A Google Book search indicates that it was well-established by at least 1890:

"Wenn Napoleon sagte: »on s'engage et puis on voit!« so bezeichnet er damit nur das Verfahren aller selbstständigeren Heerund Trnppenführer." [Monatshefte für Politik und Wehrmacht, p.284, 1889]

"Le mot de Napoléon : « On s'engage et puis on voit » a bien perdu de sa valeur." [Revue d'artillerie, Vol 39, p453, 1891]

"On s' engage et puis on voit," no longer applies. The relative smallness of armies and the smoke of battle allowed of the application of this principle, but now the general is more dependent on the reports of reconnaissances." [Journal of the United States Artillery, Vols 2-3, p119, 1893]

The earliest reference I could find (in a slightly altered form) is in Staff College Essays by Lieutenant Evelyn Baring published in 1870, though this is still 50 years after Napoleon's death.

"Napoleon's motto was, 'On s'engage partout, et puis l'on voit,' which must not be taken to mean that he began a battle without any definite plan at all, but rather that his system of fighting was so elastic that it could bend itself to suit the altered circumstances of any particular case."