Under the Monnet Plan, France—intent on ensuring that Germany would never again have the strength to threaten it—began in 1945 to attempt to gain economic control of the remaining German industrial areas with large coal and mineral deposits; the Rhineland, the Ruhr and the Saar (Germany's second largest center of mining and industry, Upper Silesia, had been handed over by the Allies to Poland at the Potsdam conference and the German population was being forcibly expelled). The Ruhr Agreement had been imposed on the Germans as a condition for permitting them to establish the Federal Republic of Germany. (see also the International Authority for the Ruhr (IAR)). French attempts to gain political control of or permanently internationalize the Ruhr were abandoned in 1951 with the West German agreement to pool its coal and steel resources in return for full political control over the Ruhr (see European Coal and Steel Community). With French economic security guaranteed through access to Ruhr coal now permanently ensured France was satisfied. The French attempt to gain economic control over the Saar was temporarily even more successful.