Here are some options depending on the context:
Formal:
* De rien. (This is the most common and literal response, meaning "you're welcome.")
* Je vous en prie. (This is a more polite and formal way to say "you're welcome.")
Informal:
* Il n'y a pas de quoi. (This means "it's nothing" or "don't mention it.")
* Pas de problème. (This means "no problem.")
* Avec plaisir. (This means "with pleasure.")
Other options:
* De nada. (This is a Spanish phrase meaning "you're welcome" and is sometimes used in French.)
* C'est normal. (This means "it's normal" or "it's no big deal.")
The best response will depend on the situation and your relationship with the person you are speaking to.