During the German occupation, a forced labour policy, called Service du Travail Obligatoire ("Obligatory work service, STO"), consisted of the requisition and transfer of hundreds of thousands of French workers to Germany against their will, for the German war effort. In addition to work camps for factories, agriculture, and railroads, forced labour was used for V-1 launch sites and other military facilities targeted by the Allies in Operation Crossbow. Beginning in 1942, many refused to be drafted to factories and farms in Germany by the STO, going underground to avoid imprisonment and subsequent deportation to Germany. For the most part, those "work dodgers" (réfractaires) became maquisards.
There were German reprisals against civilians in occupied countries; in France, the Nazis built an execution chamber in the cellars of the former Ministry of Aviation building in Paris.[28]
Many Jews were victims of the Holocaust in France. Approximately 49 concentration camps were in use in France during the occupation, the largest of them at Drancy. In the occupied zone, as of 1942, Jews were required to wear the yellow badge and were only allowed to ride in the last carriage of the Paris Métro. 13,152 Jews residing in the Paris region were victims of a mass arrest by pro-Nazi French authorities on 16 and 17 July 1942, known as the Vel' d'Hiv Roundup, and were transported to Auschwitz where they were killed.[29]
Overall, according to a detailed count drawn under Serge Klarsfeld, slightly below 77,500 of the Jews residing in France died during the war, overwhelmingly after being deported to death camps.[30][31] Out of a Jewish population in France in 1940 of 350,000, this means that somewhat less than a quarter died. While horrific, the mortality rate was lower than in other occupied countries (e.g. 75 percent in the Netherlands) and, because the majority of the Jews were recent immigrants to France (mostly exiles from Germany), more Jews lived in France at the end of the occupation than did approximately 10 years earlier when Hitler formally came to power.[32]