Germany and Poland signed the German–Polish Border Treaty, confirming their border at the Oder–Neisse line, which was originally defined by the Potsdam Agreement in 1945.

The German–Polish Border Treaty of 1990 finally settled the issue of the Polish–German border, which in terms of international law had been pending since 1945. It was signed by the foreign ministers of Poland and Germany, Krzysztof Skubiszewski and Hans-Dietrich Genscher, on 14 November 1990 in Warsaw, ratified by the Polish Sejm on 26 November 1991 and the German Bundestag on 16 December 1991, and entered into force with the exchange of the instruments of ratification on 16 January 1992.

Oder–Neisse line is an unofficial term for the modern border between Germany and Poland. The line generally follows the Oder and Lusatian Neisse rivers, meeting the Baltic Sea in the north. A small portion of Polish territory does fall west of the line, including the cities of Szczecin and Świnoujście.

The Potsdam Agreement was the agreement among three of the Allies of World War II: the United Kingdom, the United States, and the Soviet Union after the war ended in Europe that was signed on 1 August 1945 and published the following day. A product of the Potsdam Conference, it concerned the military occupation and reconstruction of Germany, its border, and the entire European Theatre of War territory. It also addressed Germany's demilitarisation, reparations, the prosecution of war criminals and the mass expulsion of ethnic Germans from various parts of Europe. France was not invited to the conference but formally remained one of the powers occupying Germany.