Here are a few long-term things they can do:
1) No money to any religion for building any house of workship, or maintaining any that is at less than 400 years old (these will all be Christian edifices, unless there's a synagogue or two that qualfies).
2) All children are taught French culture in schools. No one is taught any other culture or language (as a primary language), or any religion.
3) No government publication is made in any language except French, unless it is a matter of public health.
4) No one is allowed to immigrate unless they can prove they can contribute something constructive to the French nation.
5) French nationality is only granted to aliens if they can speak and write French. Aliens have 3 years to do this or they are deported.
6) Aliens preaching sedition against the French state are to be deported.
Nice list but most of the rioters were born in France. They can stop all immigration now but the problem will continue. Due to differences in size between the small-family metrosexual original French and the big-family, one-man-many-wives Moslem model the immigrants are still using.
Actually I think that the French require this of all of their foreign legionaires ... so why not.