Formal:
* Je veux être laissé(e) tranquille. (This is the most literal translation and the most formal.)
* J'aimerais être seul(e). (This is a more polite way to say it, implying a desire for solitude.)
Informal:
* Laissez-moi tranquille! (This is the most direct and abrupt way to say it, and should only be used with people you know well.)
* Foutez-moi la paix! (This is a very informal and rude way to say it, so use it with caution.)
* Je veux du calme. (This literally means "I want calm," but it implies you want to be left alone.)
Adding context:
You can also add context to your request by adding a reason or explanation. For example:
* Je veux être tranquille pour travailler. (I want to be quiet to work.)
* Laissez-moi tranquille, j'ai besoin de me reposer. (Leave me alone, I need to rest.)
It's important to choose the appropriate phrase based on your relationship with the person and the context of the situation.