Not trying to nitpick, but if the second generation was fairly well integrated how was it their children failed to integrate?In France the problems is with the 3rd generation immigrants from our ex North / Central African colonies.
The 1st generation came to work (or to flee like after the Algeria independance war), they settled in pretty well.
Their kids, the 2nd generation for most of them integrated well, went to the school "de la République" and most found a job.
The 3rd generation arrived at the wrong time, unemployment, failure to integrate in France, but being foreigner in their grandparents country, being ostrazied for employment and in daily life, many ended up hating "La République".
A perfect breeding ground for the Islamist recruiters, financed by some MEA countries. Or for drug importers looking for foot soldiers.
France's successive governments being completely blind and at lost how to react except by harsh police repression.
Oh, and you can't kick them out as they are French, and not even bi-national anymore. They need a visa to visit their grandparents country !
Even if they kill somebody you can't take away their nationality, as they have only one, and the rules don't allow to make somebody stateless.