Well, I'm French and live in paris.
Whilst I wouldn't focus like you on the racial aspect - which does not predispose anyone for any mean actions in case you forgot it - it is true that Paris (where I live) has become a very difficult, insecure city.
Using the subway to go back home after NYE was like going through an apocalyptic scene of drunk idiots and scum assaulting everyone, trying to touch girls, to steal purses and bags, shouting, vomiting in the metro, throwing junk out of the bins in every directions. I went home with the content of a McFlurry spread on my new suit after a stupid drunk teenager under drugs threw it at me and his five friends tried to get into an argument with me and my girlfriend. Police don't do anything and can't do anything without being heavily criticized by the whole population. There is clearly a total lack of respect, of education, of hygiene, of order in the city.
While it is obvious that many poor migrants or children of migrants take part in the riots and disrupt the quietness of other citizens, let's face it, rioting, getting drunk and revolting against order is something deeply rooted in the French culture. Poor, inoccupied people, who assault or revolt or do graffitis on the walls, among whom quite a few migrants, act in a way that is very... French. Because their own parents and also because school, the French school system, failed to educate them. A way that does not solve any problems by the way... The more it is, the more I despise the shape the French society is turning into.