200 years of not being slaves isn't enough time

they were debt slaves for a long time, you just need to catch up on your history

We also have to consider the colonial histories of these two countries. As you may know, Haiti earned its independence through a slave revolt. It was only the second country in the Americas to earn its independence (after the US). As such, many European powers, including France, Spain, and Britain, feared the precedent. These nations didn't want Haiti to become a successful and wealthy country full of former slaves, as that would have sent a message to slaves in other colonies that a revolution for independence would increase their quality of life. Thus, there was a European boycott of Haitian goods, and this lack of trade began Haiti's transition from a relatively wealthy country (by the standards of the Americas) to a poor one. To make matters worse for the Haitians, France agreed to recognize Haiti's sovereignty only after they pay a debt of 150 million francs in compensation for French​ losses during the revolution. This debt was paid over eight decades and was only fully paid off in 1922. Due to the interest on the 150 million, the Haitian government ended up paying much, much more to their former colonial owners, which did not help the financial situation. These were problems that the DR, which became independent much later, did not have to face.

One of the ways the Haitian government paid back their debt to France was in the form of massive timber exports leading to massive deforestation.

Deforestation in Haiti has been an ongoing crisis since the mid-18th century when coffee, tobacco, and sugarcane plantations were established. It has led to environmental, humanitarian, and economic crises for the nation. Reforestation has been an ongoing and difficult project. I believe only ~2% of Haiti is forested, compared to ~40% for the Dominican Republic.

It wasn't so much they felt the need to pay it off as they were compelled to. France tied the debt issue to recognition of sovereignty. If Haiti doesn't agree to pay off the debt then France will not recognize Haiti as a country which in theory could mean France could later reconquer Haiti. This wasn't an implicit threat either. France had a number of warships off the coast when the deal was negotiated. It's interesting how this issue of the debt affects relations between the two countries today, though that's for a different subreddit.

Sources:

Haiti, France and the Debt of 1825 by Anthony Phillips

Race, Reality, and Realpolitik by Jeffrey Sommers