After the end of World War II, and for three years, the victorious allies carried out the largest forced population transfer:between twelve and fourteen million people of German origin residing in the occupied countries of Eastern Europe, were expelled from their homes and forced to settle in a Germany in ruins. Put in cattle trucks or trains, the same ones that were used to deport the Jews, they suffered illness, hunger and mistreatment... In other cases, they were not directly expelled but spent weeks and months in concentration camps -somewhere took advantage of the Nazi camps-.
At the Potsdam Conference (1945) Harry S. Truman, Winston Churchill -later replaced by Clement Attlee- and Josef Stalin met to draw up the peace treaty and discuss the details of the post-war period... and the hypocritical expulsion and forced migration. The proposal came from Stalin, who had already put it into practice previously, but was supported by the US and England; only France, which was not participating in the Conference, rejected the proposal. The measure was sold as the only way to prevent violence against the German ethnic minority in the occupied countries (Poland, Czechoslovakia, Hungary…) and the creation of ethnically homogeneous states. It really was an ethnic cleansing.
In Churchill's words:
Expulsion is the method that, to the extent of our possibilities, will be the most satisfactory and lasting. There will be no mix of populations causing problems forever […] There will be a cleanup.
In practice, the measure adopted in Potsdam only ratified a fait accompli policy that the Red Army had put into practice in its advance towards Germany.
Although it is true that some residents of the occupied countries of German origin took advantage of this during the occupation and that, after the end of the war, there were some isolated cases of revenge among the civilian population, the measures adopted are not justified . Forced migration, which according to the Potsdam declaration should be orderly and humane, became a humanitarian crisis… refugees arrived in a devastated Germany with just what they were wearing.
In late 1947, the Allied Control Council stated:
Opposition to all future mandatory population transfers, in particular the forced removal of people from places that have been their homes for generations.