How do you say calm down in french?

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

Formal:

* Calmez-vous. (Formal "you" - singular or plural)

* Calmez-vous, s'il vous plaît. (Formal "you" - singular or plural, with "please")

Informal:

* Calme-toi. ("you" - singular, informal)

* Détendez-vous. ("you" - singular or plural, informal)

* Repose-toi. ("you" - singular, informal)

* Reste calme. ("you" - singular or plural, informal)

* T'en fais pas. (Slang, "don't worry" or "don't stress")

More specific:

* Prenez votre temps. (Take your time, used for a situation where someone is rushing)

* Respirez profondément. (Breathe deeply)

* Ne vous inquiétez pas. (Don't worry)

The best option depends on the situation and your relationship with the person you're speaking to.