World War I reparations means the payments and transfers of property and equipment that Germany was forced to make after its defeat during World War I.
Article 231 of the Treaty of Versailles (the 'war guilt' clause) declared Germany and its allies responsible for all 'loss and damage' of the Allies during the war and set up the basis for reparations.
In January 1921, the total sum due was decided by an Inter-Allied Reparations Commission and was set at 132 billion gold marks, about £6.6 billion or $33 billion (roughly $393.6 billion US dollars as of 2005). This was a sum that many economists believed to be too much. Later that year, the amount was reduced to 132 billion marks, which still seemed too much for most German observers, both because of the amount itself as well as the terms.
Germany stopped paying the reparations after Hitler's Nazi Party took power in 1933, with about one-eighth of the reparations having been paid by then. The final payments were made on the day exactly 20 years after German reunification.