Partisan resistance groups. Some Jews liberated from the Gęsiówka concentration camp participated in the 1944 Warsaw Uprising. In France, up to 20% of the French Resistance was Jewish despite Jews making up only about 1% of the French population, and there was a Jewish resistance unit, the Armée Juive. About 10% of Soviet partisans were Jews. Thousands of Jews also joined the Yugoslav Partisans. One Yugoslav Partisan unit, Rab battalion, was composed of entirely of Jews liberated from the Rab concentration camp. Jewish resistance in German-occupied Europe by country Belgium Belgian resistance to the treatment of Jews crystallised between August–September 1942, following the passing of legislation regarding wearing yellow badges and the start of the deportations. When deportations began, Jewish partisans destroyed records of Jews compiled by the AJB. The first organization specifically devoted to hiding Jews, the (CDJ-JVD), was formed in the summer of 1942. The CDJ, a left-wing organization, may have saved up to 4,000 children and 10,000 adults by finding them safe hiding places. It produced two Yiddish language underground newspapers, ("Our Word", with a Labour-Zionist stance) and ("Our Fight", with a Communist one). The CDJ was only one of dozens of organised resistance groups that provided support to hidden Jews. Other groups and individual resistance members were responsible for finding hiding places and providing food and forged papers. Many Jews in hiding went on to join organised resistance groups. Groups from left wing backgrounds, like the (FI-OF), were particularly popular with Belgian Jews. The Communist-inspired (PA) had a particularly large Jewish section in Brussels. The resistance was responsible for the assassination of Robert Holzinger, the head of the deportation program, in 1942. Holzinger, an active collaborator, was an Austrian Jew selected by the Germans for the role. The assassination led to a change in leadership of the AJB. Five Jewish leaders, including the head of the AJB, were arrested and interned in Breendonk, but were released after public outcry. A sixth was deported directly to Auschwitz. The Belgian resistance was unusually well informed on the fate of the deported Jews. In August 1942 (two months after the start of the Belgian deportations), the underground newspaper reported that "They [the deported Jews] are being killed in groups by gas, and others are killed by salvos of machinegun fire." In early 1943, the sent Victor Martin, an academic economist at the Catholic University of Louvain, to gather information