If I agree with some anti-privacy woes, France (and more broadly Europe) is way more privacy friendly than the US. We have to fight for it from time to time, but for now it goes mostly in the right direction.

As for religious stuff, to understand that you have to understand France. We are, due to our history, mostly irreligious (50% of the whole population in 2017), with most religious people being non-practicing. Like every country we have our religious nutjobs, but they are mostly irrevelant compared to the US ones.
As such, we as a whole generally consider that religion should not impact public life and public places nor be displayed in there, with some specific exception (nuns and priests, as it is considered as being an uniform mandated by their trade).

School is a public space, as such public display of religion are forbidden. This is not specifically agains Muslim, the same would apply to a nun when going to school as a student. Other less ostensible religious sign, like crucifixes, are also banned.
All that is (mostly) to fight communitarianism, which is viewed here as a threat to society.