How do you ask someone what is your nationality in French?

There are a couple of ways to ask someone about their nationality in French, depending on the formality of the situation:

Formal:

* Quelle est votre nationalité ? (What is your nationality?)

* De quelle nationalité êtes-vous ? (What nationality are you?)

Informal:

* D'où venez-vous ? (Where are you from?)

* De quel pays êtes-vous ? (What country are you from?)

* Quelle est ta nationalité ? (What is your nationality? - informal "you")

* D'où es-tu ? (Where are you from? - informal "you")

It's important to note that "D'où venez-vous?" and "D'où es-tu?" are more general questions about someone's origin, while the other questions directly ask about nationality.

Remember to choose the appropriate level of formality depending on the person you are speaking to.