Like many exiled German communists, by the time war broke out in 1939 he was based in France, and during 1939/1940 he was interned at Gurs. On his release he settled down to a life as a small farmer in the south of France using, appropriately, the pseudonym "Jean Bauer". During the early 1940s he worked illegally with both the French Resistance and the Soviet sponsored National Committee for a Free Germany.