How do you say I speak French fluently in French?

There are a few ways to say "I speak French fluently" in French, depending on the level of formality you want:

Formal:

* Je parle français couramment. (This is the most common and literal translation.)

* Je maîtrise le français. (This means "I master French," implying a high level of fluency.)

Informal:

* Je parle français comme une langue maternelle. (This means "I speak French like a native speaker.")

* Je suis bilingue en français. (This means "I am bilingual in French.")

* Je parle couramment français. (This is a more colloquial way of saying "I speak French fluently.")

Note: You could also use the verb "dominer" (to dominate) in place of "maîtriser," though this is a bit less common and might be considered too strong for some situations.

The best option for you will depend on the context and who you are talking to.