The Economist explains why the French left supports the ban. The magazine's final paragraph:
Conseil d’Etat, the highest administrative court, has expressed worries about the legal grounds for a ban. If passed, Mr Copé says that it will apply not only to French Muslims, but to visitors from the Middle East too. Would such women be fined while doing their shopping on the Champs-Elysées? How can the government be sure that a woman is wearing the burqa under orders from her menfolk? Would it not lead to their further isolation, as they felt unable to venture out of the home? If that were indeed the upshot, it would be paradoxical for a law designed in part to ensure equality for women.
I have to say this encroaches too far on religious liberty for me. I find the burqa repulsive for any number of reasons, and the subjugation of women it represents appalling. But freedom for me is a more important value. I do not want to live in a society where such things are banned. It means that other things can be banned for the good of others. And we're not French, are we? A reader puts this a little more colorfully:
I get really pissed when people say a woman in America, or any other western country, should be banned from wearing anything she frickin feels like wearing. When I was a youth I had piercings, a mohawk, I wore doc martens and tried my best to look as scary as possible. I was punk rock, baby, and I loved it. And if anyone told me not to wear what I wanted, well I didn't give a shit. I was expressing my rebellion when I wore those clothes for everyone to see. Woman in burqas, veils or whatever are expressing their relationship with their God, and by extension their society, and accepting whatever harsh treatment they receive because it it, just like me with my punk rock clothes.