Germany was known as the Weimar Republic during the years 1919 to 1933. It was a republic with a semi-presidential system. The Weimar Republic faced numerous problems, including hyperinflation, political extremism (including violence from left- and right-wing paramilitaries), contentious relationships with the Allied victors of World War I, and a series of failed attempts at coalition government by divided political parties. Severe setbacks to the German economy began after World War I ended, partly because of reparations payments required under the 1919 Treaty of Versailles. The government printed money to make the payments and to repay the country's war debt, but the resulting hyperinflation led to inflated prices for consumer goods, economic chaos, and food riots. When the government defaulted on their reparations payments in January 1923, French troops occupied German industrial areas along the Ruhr and widespread civil unrest followed.