How do you say You need to calm down in french?

There are several ways to say "You need to calm down" in French, depending on the context and the level of formality:

Formal:

* Il faut que tu te calmes. (It is necessary that you calm down.)

* Calmez-vous, s'il vous plaît. (Calm down, please.)

Informal:

* Calme-toi ! (Calm down!)

* Relaxe ! (Relax!)

* Respire ! (Breathe!)

* T'es stressé(e) ! (You're stressed!)

More specific:

* Tu dois te calmer. (You must calm down.)

* Prends une pause. (Take a break.)

* Essaie de te détendre. (Try to relax.)

Important Note: The choice of expression will depend on the situation and your relationship with the person you are addressing.