My French ancestors were from Normandy (before leaving for Quebec in 1648), so its very disheartening, to learn that Normandy is no longer safe.
France needs to grow a spine, and end its policies of mass immigration. They should also consider deporting, some of the people they have allowed in.
If the Polish people's Republic could steal Germany territory (Neumark, Schleisen, Pommern, Ostpreussen) and expel millions of Germans (without compensation), from their own homes, then surely France can find some legal mechanism for reversing its mass immigration policies.
The Czechs got away with expelling 1/3 of their pre WW2 population (mostly ethnic Germans), and those people had been there since the 13th century (when the Bohemian monarchy promoted German settlement in Bohemia). Therefore, there is legal precedent for deporting people from France.