yeap. This is due to the way students are selected after high school. engineering schools are much difficult to enter than universities ( because universities in france theorically don’t have the right to select first year students based on grades... yeah i know...)

So, the most valued way to do research in france is actually to first do one of those highly competitive schools first, then go to university for a phd.

But culturally, companies pay a lot more attention to the kind of engineering school you’ve been to than to your phd.