What is the history of teaching assistants (TAs) in France?

I know that in France—as late as the early 20th century, although I'm not sure if this is true now—a university student (undergrad or grad?) would take a nationwide concours exam to receive the aggrégation "to be aggregated" in the French school system and be able to teach at lycées ("high schools"?), académies (universities), and grandes écoles.

Was one with an aggrégation essentially a TA?

I know that in France, as late as the early 20th century, although I'm not sure if this is true now, a university student (undergrad or grad?) would take a nationwide concours exam to receive the aggrégation "to be aggregated" in the French school system and be able to teach at lycées ("high schools"?), académies (universities), and grandes écoles.

Was one with an aggrégation essentially a TA?