[Tripper]

It's the disaffected youth becoming fed-up with authority.

Basically years ago France invited a bunch of North Africans (Algerians etc) into the country and gave them project-like towns just outside of the bigger cities to live in - At the time this was better than anything these people were currently living in, so they moved in voluntarily.
Over the years, the French government started to neglect these areas, and just recently cut spending on these ghettos in education and health etc, and when you do that, unemployment increases tenfold. There is a huge amount of unemployment in these areas, its crazy.

Kids go crazy and start rioting after just being fed-up and feeling like noone gives a shit about them. The government even said after this happened that they made a mistake and will increase spending on these areas to help solve the problem.