To blame France riots on the racism of French people toward the Muslim migrants is as ludicrous as to blame the downfall of the Roman empire on the racism of Romans towards the barbarian mercenaries.
Yet there is something hidden in there.
There is an attitude of the top elite that elected to invite migrants in one case and recruit the barbarians in another. It is not racist per se, it is worse. It is indifferent. It just does not care.