But this is only to be expected. The last I heard, there were parts of the Paris suburbs that were so hostile to non-Arab police officers that the police began refusing to even enter those areas to attempt to quell rioting and general lawlessness that has persisted since the beginning of the rioting in 2005.
If you don't go in there and root out the problem, it's just going to spread. The same goes with ignoring the problem, or pretending that there is no issue to be dealt with.
If they continue to be big do-nothings regarding the latent racial/religious tensions, next year it won't just be burning cars and smashing windows.