At the beginning of 1923 the German government stopped paying reparations, because it could no longer afford to do so.
France and Belgium responded by sending troops into the Ruhr, an area which produced 80% of Germany’scoal and iron. They confiscated materials and goods as compensation for the lost reparations.
Since the Germany army was too small to fight against the French and Belgian troops, the government instructed the miners to stop work so that the invaders could not take the goods they produced. This was called passive resistance.
The Government had to print money to pay these workers and to make up for the Governmental income they lost from the Ruhr. This triggered hyperinflation.