In the 1920's The German state was unofficially known as the Weimar Republic. This name was used between 1919 and 1933 until the Nazi party came into power.
The official name of the state during this time was Deutsches Reich, kown as the Germany Realm in English. The capital of the republic was Berlin and the population was nearly 60 million.
In its 14 years of existence, the Weimar Republic a lot of problems with the economy, labor, loans and inflation. However, by the 1930s the country had stablized and was in a much stronger position than it was after World War I.