He was released from Berlin's on 22 April 1945 as the Soviet army took possession of what remained of the city. The end of the war marked a return for Lehmann to mainstream politics in what was administered, between May 1945 and October 1949, as the Soviet occupation zone. During May and June 1945 Lehmann worked with the economy department in the Berlin municipal quarters of Pankow and Wedding. Then, through July 1945, he served as deputy chief of the Social Security Establishment for Greater Berlin, a position from which he moved on to create the National Administration for Labour and Welfare Affairs ("Zentralverwaltung für Arbeit und Sozialfürsorge") in the zone relaunched, in October 1949, as the Soviet sponsored German Democratic Republic, retaining responsibility within that organisation as a vice-president of it till 1950.