> French companies, especially large ones, have a really strong bias towards applicants from well known and somewhat elitist public schools,

Not only French companies, but also banks, hedge funds, companies like Google and so on...

I was saying that in an other comment, but recently Google Paris organized a programming contest. All teams in the top ten came from top schools (mainly ENS, but also ECP and X) whereas 42 performed extremely poorly.

There's a reason why employers are biased towards elite schools.