The root cause of the French riots is its immigration policies. Without fundamental change there, France, and much of the rest of Europe, will see more riots. From Alain Destexhe at gatestoneinstitute.org:
These responses — skirting due process at the highest levels of government — show the fear that the suburbs instill in those in power: the fear of a generalized conflagration, the fear of another death, the fear that control of the situation is slipping away, the fear of the inability to control these uprisings or the root causes that breed them.
Some of these suburbs have long since become lawless zones, or rather zones of “alternative law,” where drug kingpins and Muslim imams now rule the roost, and where the police only move in force from time to time. In some neighborhoods, drug dealers have set up physical obstacles that make it difficult for the police to gain access when they decide to intervene by force, when the authorities can pretend that they still control something.
It is necessary to deal with the cause — excessive and uncontrolled immigration — both legal (through family reunification and the right of asylum) and illegal. When you are faced with a leak in a boat that is on the verge of sinking, as French society is, you not only have to have to bail out the water, but also plug the breach.
