Why is French spoken in Martinique?

La Martinique is a French oversea possession. People living there are French citizens. The same goes for La Guadeloupe and French Guiana in the same area.
because they are a reigon of france
Martinique is an overseas department of France (similar to a US territory such as Puerto Rico).
Martinique is a part of France so French is the official language. They also speak other languages too, including the Martinique creole (akin to the Haitian creole, but closer to French).
La Martinique is a French oversea possession. People living there are French citizens. The same goes for La Guadeloupe and French Guiana in the same area.