Denaturalisation
According to philosopher Giorgio Agamben, France was one of the first European countries to pass denaturalisation laws, in 1915, with regard to naturalized citizens of "enemy" origins. Its example was followed by most European countries.
As soon as July 1940, Vichy France set up a special Commission charged of reviewing the naturalizations granted since the 1927 reform of the nationality law. Between June 1940 and August 1944, 15,000 persons, mostly Jews, were denaturalized. This bureaucratic decision was instrumental in their subsequent internment.
Read more about this topic: French Nationality Law