Wait, they paid France because they were slaves? Explain that.
I'm sure that you know they agreed to pay huge reparations to France for having been slaves.
Haiti (Sainto Domingo then I think) was a French colony that used slave labor to grow mostly sugar. During the same period that Napoleon was trying to conquer Europe the slaves rose up in a bloody revolt. Because the French army was busy trying to take over the world in Europe they made a deal to grant Haiti their independence from France but in return for not sending in the military the French got the Haitians to agree to pay reparations for the financial sacrifice of freeing the slaves and land. It was a fairly large amount - in the billions in today money - which was finally paid off in the 1940s. I think.
This treaty with Haiti caused the French to decide to just cut their losses in the new world and raise a bit more money to pay for their European adventure by selling the Louisiana territory to the young US of A for something like 12 cents and acre - thus tripling the land mass of the United States for like a case of beer.
Haiti was one of the first countries in the new world besides us to win their independence. They started out deep in debt, and have been poor ever since.
If the Haitian slaves had not of revolted we probably would not have acquired the Louisiana purchase, and most of you people west of the Mississippi might be either Mexicans or French. Imagine that.
You should look into it though because most of the crap I spout I make up as I go along.