The reparations were determined by the Treaty of Versailles, which was signed by Germany in 1919. The treaty required Germany to pay 132 billion gold marks (approximately $33 billion) over a period of 30 years. This amount represented about 10% of Germany's pre-war national income.
The reparations payments were a heavy burden on the German economy and contributed to the country's economic problems in the 1920s. The Dawes Plan of 1924 and the Young Plan of 1929 were attempts to reduce the burden of reparations, but they were ultimately unsuccessful.
In 1932, Germany defaulted on its reparations payments, and the Allied Powers took control of German customs and other economic assets. This further damaged the German economy and contributed to the rise of Adolf Hitler and the Nazi Party.
The reparations payments were finally ended in 1933, after Hitler became Chancellor of Germany. Hitler repudiated the Treaty of Versailles and Germany's obligation to pay reparations.