German workers who were initially forced to work on the "West Wall" or later in various factories were sent to the camp as of 1939 on the charge that they had insufficient work discipline or demonstrated "asocial behaviour". There they were supposed to be 'retrained' according to the National Socialists understanding of training. The camp in Hinzert operated as a "work training camp" not only for German workers, but also for forced labourers from occupied countries during the war. After the armistice agreement in 1940, Germans and foreigners that served in French foreign legions were added. It was in this manner that 437 foreign legions, for example, were transferred from the internment camp Fréjus to Hinzert in July 1941.
Large groups of prisoners came primarily from Luxembourg. The Gestapo had most of the resistance fighters from this country locked up in the Hinzert camp which was close by. Extensive transports of prisoners also arrived at Hinzert from France, Poland and the Soviet Union. The prisoners from Western Europe were mostly political resistance fighters. The Eastern European prisoners primarily consisted of forced labourers deported to Germany. After the Wehrmacht High Command issued the "Nacht-und-Nebel" Decree (Night and Fog Decree) on 7 December 1941, almost 2000 Frenchmen, but also Belgian and Dutch members of national resistance groups were deported to Hinzert from May 1942 to October 1943. The "Nacht-und-Nebel" prisoners (NN prisoners) were supposed to disappear from their homelands without a trace and be deported to Germany in the utmost secrecy, so that they could be assigned to a special court for sentencing. Family members received no information about the location of prisoners. NN prisoners were strictly forbidden letter contact. They generally came to Hinzert via the Trier prison. From here they were later brought to other penal institutions (e.g. Wittlich and Diez), which were close to a special court (e.g. Cologne, Wittlich), or to other concentration camps.
In February 1943 the SS regulated the question of what to do with Polish forced labourers that had "traces of Nordic blood" and had had forbidden relations with an "imperial (reichsdeutsche) German woman". Polish men to whom this applied were to be reviewed for their "ability to become German". The time frame for such a review was set at six months. The instructions issued on 4 June 1943 stated that this group was to be brought to the SS Special Camp in Hinzert for the length of this "review".