War ended, formally, in May 1945 and Maria Rentmeister was released. Her prison and her home region were now under military administration as part of the British occupation zone. Maria, along with most of her relatives, relocated to the large central portion of Germany which was being administered as the Soviet occupation zone, and would be relaunched in October 1949 as the Soviet sponsored German Democratic Republic (East Germany). Communist Party membership was no longer illegal, and she took a lead in re-establishing a party branch in Dessau, where work was starting on rebuilding the destroyed town, between May and July1945. She was soon able to move to Berlin, less than 100 km to the northeast, where during the Summer of 1945 she worked for the party on culture related matters. From 1945 till its dissolution in November 1947 she also served as chair of the Berlin party Women's Committee. A new political party was formed under contentious circumstances in April 1946 as a result of which Rentmeister was one of many thousand committed communists who signed their party memberships across to the new &lt;a href="Socialist%20Unity%20Party%20of%20Germany"&gt;Socialist Unity Party ("Sozialistische Einheitspartei Deutschlands" / SED)&lt;/a&gt;, which over the next few years would go on to become the ruling party in a different kind of German one-party dictatorship.