波茨坦协定
The decision to move the Polish border westward was made by the Allies at the Tehran and Yalta Conferences and finalized in the Potsdam Agreement, which also provided for the expulsion of German citizens to Allied occupation zones. Although the Potsdam Agreement left the final decision about the border shift to a future peace treaty, the Polish government (which had implemented pre-Potsdam expulsions from the Oder–Neisse line area) interpreted it as final decision which would be confirmed by the peace treaty. In reality, the Potsdam Agreement took its place. The status of the expellees in post-war West Germany, which granted the right of return to the German diaspora, was legally defined in the Federal Expellee Law of 1953.