Here are some other options, depending on the context:
* Collègue de classe: This is a more formal way to say "classmate" and is often used in university settings.
* Condisciple: This is a more literary term for "classmate" and is not used as frequently as "camarade de classe".
* Étudiant(e): This simply means "student" and can be used to refer to a classmate, but it is not as specific as "camarade de classe".
The best way to choose the right word is to consider the context and the level of formality you want to convey.