“Croissant” is a French word so of course you can use it in French. But you need to know that the name of this delicious pastry is related to its shape. “Croissant” means “crescent.” Just like the crescent of the moon.
Now that it all makes sense, please don’t look for chocolate croissants in France: unlike in the US, they are not a thing! They are called “pain au chocolat.”
J’aime manger des croissants au petit-déjeuner (I like to eat croissants for breakfast.)
Le pain au chocolat n’a pas la forme d’un croissant ( The “pain au chocolat” doesn’t have the shape of a crescent.)