As one thing leads to another..........

      For the French, helping the American rebels held obvious allure.  It presented an opportunity to avenge their defeat in the Seven Years' War.  True, the territorial loss of Canada could be exaggerated—Voltaire infamously dismissed Canada as "a few acres of snow."  It was also true the economic impact of the defeat could be exaggerated—France retained control over her Caribbean colonies, where enslaved Africans produced the sugar, coffee, and cotton generating the real wealth of the French colonial empire. But statecraft was not all hard economics: pride and prestige were important, too.  Since the end of the last war, the French had wallowed in national resentment.  Any chance to knock the British down a peg was a chance worth taking.  The public certainly seemed enthusiastic.  When the rebellion in America broke out, the cause of les insurgents became all the rage in French society.

-Mike Duncan, Hero of Two Worlds: The Marquis de Lafayette in the Age of Revolution