http://en.wikipedia.org/wiki/Weimar_Republic

In the early postwar years, inflation was growing at an alarming rate, but the government simply printed more and more banknotes to pay the bills. By 1923, the Republic claimed it could no longer afford the reparations payments required by the Versailles Treaty, and the government defaulted on some payments. In response, French and Belgian troops occupied the Ruhr region, Germany's most productive industrial region at the time, taking control of most mining and manufacturing companies in January 1923. Strikes were called, and passive resistance was encouraged. These strikes lasted eight months, further damaging the economy and the social life.
The strike prevented some goods from being produced, but one industrialist, Hugo Stinnes, was able to create a vast empire out of bankrupt companies. Because the production costs in Germany were falling almost hourly, the prices for German products were unbeatable. Stinnes made sure that he was paid in dollars, which meant that by mid-1923, his industrial empire was worth more than the entire German economy. By the end of the year, over two hundred factories were working full-time to produce paper for the spiralling bank note production. Stinnes' empire collapsed when the government-sponsored inflation was stopped in November 1923.
In 1919, one loaf of bread cost 1 mark; by 1923 the same loaf of bread cost 100 billion marks.


One-million mark notes used as notepaper, October 1923.

Since striking workers were paid benefits by the state, much additional currency was printed, fueling a period of hyperinflation. The 1920s German inflation started when Germany had no goods to trade. The government printed money to deal with the crisis; this meant payments within Germany were made with worthless paper money, and helped formerly great industrialists to pay back their own loans. This also led to pay raises for workers and for businessmen who wanted to profit from it. Circulation of money rocketed, and soon banknotes were being overprinted to a thousand times their nominal value and every town produced its own promissory notes; many banks & industrial firms did the same.
The value of the Papiermark had declined from 4.2 per U.S. dollar at the outbreak of World War I to 1 million per dollar by August 1923. This led to further criticism of the Republic. On 15 November 1923, a new currency, the Rentenmark, was introduced at the rate of 1 trillion (1,000,000,000,000) Papiermark for one Rentenmark, an action known as a monetary reset. At that time, one U.S. dollar was equal to 4.2 Rentenmark. Reparation payments resumed, and the Ruhr was returned to Germany under the Locarno Pact, which defined a border between Germany, France and Belgium.
Further pressure from the right came in 1923 with the Beer Hall Putsch, also called the Munich Putsch, staged by the NSDAP under Adolf Hitler in Munich. In 1920, the German Workers' Party had become the National Socialist German Workers' Party (NSDAP), or Nazi Party, and would become a driving force in the collapse of Weimar. Hitler named himself chairman of the party in July 1921. On 8 November 1923, the Kampfbund, in a pact with Erich Ludendorff, took over a meeting by Bavarian prime minister Gustav von Kahr at a beer hall in Munich.
Ludendorff and Hitler declared that the Weimar government was deposed and that they were planning to take control of Munich the following day. The 3,000 rebels were thwarted by the Bavarian authorities. Hitler was arrested and sentenced to five years in prison for high treason, a minimum sentence for the charge. In the event, he served less than eight months in a comfortable cell, receiving a daily stream of visitors before his release on 20 December 1924. While in jail, Hitler dictated Mein Kampf, which laid out his ideas and future policies. Hitler now decided to focus on legal methods of gaining power.