très faux

You usually place it after the verb être (to be). For example, C'est très faux means "That is very false." You can also use it with the verb chanter (to sing). If you are talking about an object, like a fake diamond, you might use it there too. However, it most often applies to statements or sounds. It is an adjective phrase, so it is very flexible. Just remember that faux changes to fausse for feminine nouns.

Use it when you hear a blatant lie. Use it during a trivia night when someone gets a date wrong. It is perfect for correcting a mistake in a meeting. You can also use it playfully with friends. If a friend claims they can run a marathon in an hour, tell them it is très faux. In music class, a teacher will use it for a missed note. It is a very common, everyday expression across France.

Do not use it to describe a "bad" person. For a mean person, use méchant. Do not use it for "fake" emotions usually. For that, hypocrite or insincère works better. Avoid using it if someone is just slightly mistaken. It can sound a bit harsh or blunt. If you want to be polite, try Ce n'est pas tout à fait ça. Très faux is for big, obvious errors.

French culture places a high value on logic and precision. Being "wrong" is seen as a specific state, not just an opinion. In the French school system, faux is the standard mark for an incorrect answer. There is less "participation trophy" culture here. If it is wrong, it is simply faux. Musically, the French are quite sensitive to chanter faux. It is a common critique on French talent shows.

You might hear complètement faux for "completely false." Another one is tout à fait faux, which means "entirely false." If someone is lying through their teeth, you say C'est archi-faux. That is a more informal, emphatic version. For a small mistake, you just say C'est un peu faux. If you want to sound more formal, use inexact instead.