My understanding is that these areas were pretty much lawless before the riots. I think the police crackdown proposed by the Interior Minister stepped on the gangs toes, and that it was gangs, made up of Muslims, that started these riots.
re#153
This has been brewing for some time. Here's a very telling article written 3 years ago (long but worth the read--chilling):http://www.freerepublic.com/focus/f-news/1515278/posts