Protest (to include property destruction) is a core component of French culture and both expected and generally tolerated even when disapproved of and quashed or, more typically, allowed to fizzle out on its own.

French national soccer team lost? Burn cars to show disapproval. Team won? Burn cars to celebrate.

Seems to me that that cultural aspect + general teenage angst + current generation’s diminished prospects + French national debt + seedy element’s use of more-peaceful protests as an excuse to piggyback in order to commit violence and destroy property for fun = current situation.