I feel obligated to respong to all this, being another frenchman and all.
On the original topic of the thread : yikes. Banning a skirt for being too long (and vaguely reminiscent of religious garb) was stupid and offensive. I facepalmed the fist time I got in contact with that story.
On the topic drift : well, yeah, France does have a tradition of being agressively non-religious, as far as our institutions are concerned. As someone who is pretty anti-religion myself (or at least, who feels that religious fee-fees have no fucking place in public discourse when talking about the way the country is run) I'm of the opinion that it's a good thing. The kicker is that the way anti-religious laws are usually enforced ends up pushing even harder against opressed groups, which is pretty shitty.
I'm seriously torn up on the issue.
PS : Also, to clarify, you totally can wear religious garb out in public. That's not against the law. You are not allowed, however, to wear a kippa or a hijab or a tshirt with a cross when in a governement-funded place. That goes for schools, mairies, government buildings, army barracks, etc. By all means, wear everything you want when going out for a coffee.