I haven't posted anything about the riots, mainly because I don't know that much about comtemporary French society. Thus other than cringing at the seemingly ubiquitous "Well, of course, cuz ya know, them damn Muslims are causing trouble everywhere" or "Wow, 2 French groups fighting each other? Well why haven't they both surrendered yet?" type of rubbish, I don't really have much to offer to the conversation.
I did, however, run across a very good post here by Juan Cole (professor of history at UMichigan). It's a little oblique in that it really discusses popular American perceptions of what's going on, but there's some great insight in it about French society (in all its colors and manifestations) that are helpful in getting a handle on what the hell is going on over there. There are some arguments in it that I suspect of being straw men (I myself have never heard anyone say that the riots are the current manifestation of the 1300 year old struggle between French Christians and Arab Muslims), and other parts where it labels ideas as "right wing" that I think are more broadly American, but other than that, he has some sound arguments. It's brief and worth a read.