Why was Khomeini in France? Who allowed him to leave and why?

France supported the Iranian revolution. Just before the revolution, they took khomeini to Paris in order to facilitated the revolution and guarantee his safety until his return to Iran.

Well, that seems to be an oversimplified version of the story to me. Many other things also happened and although some of them were like conspiracy theories but there are many other facts that are good to be known. Just for mentioning one of them; it is good to know that Le Monde newspaper had an interview with Khomeini in May 6, 1978. This is months before Khomeini went to France and recieved extraordinary media coverage thereafter. You can also check the following link and again although you may see it as one of baseless conspiracy theories, there are interesting facts in it that are good to know: http://www.globalresearch.ca/the-real-iranian-hostage-crisis-a-cia-covert-op/5324385?print=1

France was a "neutral" country (relative to the Middle East). While some probably suspected that Khomeni was a "troublemaker," no one in France attached to him the importance that he would soon have. Khomeni thought about seeking political asylum in France, but decided to "stay under the radar." The decision NOT to seek asylum ensured that France would not pay much attention to him.

Khomeni left France early in 1979 to return to Iran when the Shah left Iran. With regard to France, he basically came and went as he pleased, for his own purposes. No one in France had any real incentive to stop him, and no one did.

Khomeini was in France because he had been expelled from Iran and then Iraq, and his aides had advised him to go to Europe, and because France granted him political asylum. He was at the time an aged and relatively obscure religious figure, a target of political persecution who had not been to his home country in well over a decade. They probably saw him as harmless.

He was allowed to leave because he had broken no French laws, nor done anything else that would cause the French authorities to force him to stay.

I'm sure within a few years, with French hostages in Lebanon and bombings in Paris over the Lebanese crisis, the French regretted both decisions— but that is hindsight, and hindsight as they say is 20/20.

Ruhollah Khomeini came to prominence for opposing various actions and policies of the government of Shah Mohammed Reza Pahlavi in the early 1960s, such as removing the requirement for public officials to swear oaths on the Koran, and the appropriation and redistribution of land from religious estates. He was imprisoned and kept under house arrest for a period, then on November 4, 1964 deported to Turkey.

He remained in Turkey less than a year, then relocated to Najaf in Iraq, where he spent most of the remainder of his exile. He continued to agitate against the shah's regime, and as antigovernment sentiment intensified in Iran throughout 1978, the imperial government wanted to increase his physical distance from Iran. They pressured Iraq to expel Khomeini, and he was deported to Kuwait on October 6, 1978.

He had originally planned to relocate to Syria, but his aides noted that he would be monitored and highly restricted if he stayed anywhere in the Middle East. He requested and received political asylum in France instead, and on October 8 he relocated to a rented house in Neauphle-le-Château outside of Paris.

The move was a huge boost to his cause. It put him within reach of the international news media and sympathetic (at least in their opposition to the shah) intellectuals, but perhaps more importantly, the phone infrastructure in Europe was far more reliable, enabling him to stay in close touch with contacts in Iran and participate in the groundwork for the post-imperial regime. If he had stayed in southern Iraq, who knows whether he would have had such a profound influence on subsequent events.