How do youu say he is french?

Here are a few ways to say "he is French" depending on the context:

Formal:

* He is French. (This is the most straightforward option)

* He is a French citizen.

* He is of French nationality.

Informal:

* He's French.

* He's from France.

To emphasize his origin:

* He's a Frenchman.

* He's French by birth.

The best choice will depend on the situation and the desired level of formality.