The treatment of Germany by the Entente Powers and the United States after World War I was vastly different from how it would be treated by the Allied Powers following its surrender during World War II.
At the end of the First World War, Germany, not unexpectedly, was treated as defeated pariah nation. Under the conditions set forth in the Treaty of Versailles, Germany was forced to pay reparations to the victors, give up territory that included sizable ethnic German populations, and was restricted in how it could rebuild its armed forces. When, Germany could no longer make reparations payments, in January 1923, France and Belgium occupied the Ruhr, Germany's most important industrial zone. They would withdraw in 1925, but the humiliation from the occupation, combined with the restrictions on its military and its continued treatment as a pariah nation exacerbated the already seriously wounded pride of a very nationalistic people. The bitterness, greatly exacerbated by the onset of the Great Depression and the massive levels of unemployment it caused, set Germany on the path towards the fascism represented by Adolph Hitler and his National Socialist Party (the Nazis).
The treatment of Germany at the end of World War II reflected the Cold War tensions between the United States and the Soviet Union that had existed throughout the war and now were manifesting themselves in competition for influence in the post-war world. Also, the United States and Great Britain had learned from the failure of post-World War I policies to prevent another large-scale conflict. The half of Germany, and of the city of Berlin, that would remain under U.S., British, and French control was treated as a defeated nation, but one that had to be rebuilt along democratic lines. The Soviet Union, which would hold a tight grip on East Germany for the next 45 years, wanted to both prevent any possible resurgance of German military might that be used against Russia, and to create a police state in its own image. Consequently, the post-World War II treatment of Germany has two distinct parts: the U.S.-dominated west, and the Soviet-dominaed east.