There are "good" French companies where you can grow a career and get a good salary.
What surprises me is that these companies seem to either hide their French roots, and are often ignored by the academic world. When I was student in engineering school, the only companies we would hear from where the big French corps like Orange, Cap Gemini, Thales and co.
I'm sad to see that these French companies don't get the support and publicity they deserve. I hoped that the French tech thing would help these companies, but I only ever hear about startup with vague pitches founded by business school graduates which don't know a thing nor care about any "tech".