Sorin’s comment says (in part):
If, on the other hand, he is an alumnus of one of the “Grandes Ecoles” (which are themselves finely ranked), then it means that guy has what it takes to compete in the system.
I believe that competing in the education system is different than success at work. I had a completely undistinguished academic career. I’ve been much more successful at work than I ever was in school. I don’t think I’m alone. That’s one of the reasons I don’t count education (success in admission to some school or taking some classes) as a predictor of work success.
Let me ask this question of you, my readers: Have you found that education success is a predictor of work success?