It's equivalent mostly in terms of cultural significance (historical university etc..) . It's still one of the best university in France in terms of reputation and name recognition for a "university". Grandes écoles form a parallel track that gathers the best students due to a very selective and tough entrance process (2 years of intense preparation). Universities can still have great programs and do great research (and really smart students who didn't want to do the Prépa), but there is a certain little extra for having gone to a grande école.

Now, apart from some programs at specific universities, there is not much difference in universities in France at undergraduate level, acceptance is high because getting the French baccalaureate (high school diploma) guarantees access to universities. With the new system it might not be your first choice program, though before that meant basically a 100% acceptance rate at undergraduate level (this needs to be updated). Selection happens throughout the course as people drop out or fail exams. The stats were quite telling before.

Also, because there is not much difference between unis, people tend to go to whatever was closest to home for undergraduate studies.

my bad, overlooked ENS ..

> Merit seems to be totally non existent.

I think that's a bit of an exaggerated extrapolation of your observation based on already treated data. Family backgrounds surely plays a definitive role but not in a way that affects merit, especially for engineering schools. The exams are tough and only the best succeed (ie merit). It's how one gets to be the best that's the problem, as mentioned above, the right family background will give you the right environment to succeed. However even if given that, you still suck at maths, no one will help you.

Family legacy is not an admission criteria, unlike some other countries. For those top schools, selection committees look at your grades at the exam and that's it. No need for weird ever lasting list of extracurriculars, or to know who your father is, or how much money they can donate.

OP wrote Nobel, so I understood it as having a Nobel prize winning family name. :D

ENA is not "a best university", it's basically a specialized school to be in the highest ranking public service careers tracks. One usually goes there if they pass the entrance exam, which is usually taken after obtaining at least a masters level degree.

The other ones on the list are business schools and engineering schools. I would say the "best" one here being polytechnique (engineering school). The entrance exam is merit based (maths and physics), but there is a socio-cultural bias as to who ends up succeeding (ie your parents taught you the right priorities during you schooling, and knew how to give you the best opportunities, which is obviously easier if they went through the process themselves.).