Informal:
* Pas de problème: This is the most common and versatile way to say "no problem."
* Aucun problème: Similar to "pas de problème," but slightly more emphatic.
* Y a pas de souci: This is a more casual expression, meaning "no worries."
Formal:
* Il n'y a pas de problème: This is a more formal way to say "no problem," and it is often used in professional settings.
* Ce n'est pas un problème: This is also a formal way to say "no problem."
Other options:
* Avec plaisir: This means "with pleasure" and can be used when you are happy to do something.
* De rien: This means "you're welcome" and can be used to respond to a thank you.
The best way to say "no problem" in French will depend on the situation and the people you are speaking to.