From 1929 on , he worked at Osram in Berlin - Moabit and joined the KPD workplace cell .
He joined the Communist Party of Germany ( KPD ) in 1920 and took several courses at the Marxist Workers ' School .
From 1929 on , he worked at Osram in Berlin - Moabit and joined the KPD workplace cell .
He joined the Communist Party of Germany ( KPD ) in 1920 and took several courses at the Marxist Workers ' School .