"For many years following World War II, German politics was something of a predictable affair. There were basically three parties to choose from: the Christian Democrats (or the Christian Social Union if you lived in Bavaria) on the center right, the Social Democrats on the center left and the Free Democrats for adherents of the free market. The latter played junior coalition partner to whichever of its larger brethren came out on top in elections. ANZEIGE That model, however, began to change with the emergence of the Greens. Indeed, it was seen as a minor revolution in 1998 when a Joschka Fischer-led Green Party helped the Social Democrats into the Chancellery behind Gerhard Schröder."

http://www.spiegel.de/international/germany/guide-to-german-political-parties-a-886188.html