The German economy had shattered under the stress of The War, and paying the reparations cost them nearly all of their precious metals.  Without them to back their economy, hyperinflation soon made it impossible to pay, and they began to default on the payments.  The French, indignant that the Germans would honorably sign a treaty and then not follow it, sent troops into Germany to confiscate raw materials.  The German people did not cooperate.  Many died.