German communities living within the pre-war borders of Poland participated in wartime German activities , starting with the invasion of Poland . Created on order of Reichsführer-SS Heinrich Himmler , a Nazi ethnic German organisation called Selbstschutz carried out mass murder during '' Intelligenzaktion '' alongside operational groups of German military and police . In addition , the German minority engaged in such activities as identifying Poles for execution and illegally detaining them . To Poles , moving Germans out of Poland was seen as an attempt to avoid such events in the future and , as a result , the Polish government in exile proposed a population transfer of Germans as early as 1941
Intelligenzaktion
Intelligenzaktion
Flight and expulsion of Germans from Poland during and after World War II