Let's allow the French-born children of immigrants to grow up within the mythology of being French, one France, all equal under possibility and under the law. Let's take every opportunity to reinforce this mythology that anyone born in France is equal with every other person born in France. (Oh, and France has no ghettos.)
Let's take every opportunity to strip any visible cultural heritage from them at the growing-up stage -- for in France, you are French, yes? (No matter that it just so happens that the only religions affected at their core happen to be non-Christian.) Above all, we don't want their parents to brainwash them into a cultural system that shouldn't be theirs, equal opportunity and all that ... although we can allow them to build private schools if they want, once they have the local community money to build and support them: the second generation is French after all, equal under the law of economics.
After all, no one can say we did not learn from the example of the Canadian aboriginal residential schools.
Let's finally release these second-generation children out of an education severed, made barren of their roots. Let them venture into the working world as equals with every other French-born child raised within the same structure, empty of their own heritage, filled with the natural expectation that they, as much as any native son of France, have with everyone else an equal chance to succeed under the law: for France is secular and colour-blind.
Cover from all the media and let simmer for a few decades. A few odd incidents in a few (not-really French) suburbs are a non-story after all: and it is our patriotic duty to ensure that business and tourists and exchange students recognise that they remain perfectly safe, please do continue to invest your money and to visit? (but just not those parts of the cities).
Then, when the mixing pot begins to boil over, let's impose a law dating from colonial times, enacted specifically for the purpose of subduing native unrest in Algeria; and let's also deport anyone involved who did not have the fortune to be born in la belle France. That ought to demonstrate to the young marginalised second-generation men of African and Muslim descent beyond any shadow of a doubt that they are truly French.