The debt levels of European countries have reached new highs since the beginning of the financial and economic crisis. To finance this debt, the states had to perform numerous new issues of government bonds. With an outstanding volume of around 7 trillion Euro, the European government bond market is one of the largest and most important capital markets in the world. In this thesis I analyse the trades taking place in the two submarkets of a government bond market, the primary market and the secondary market. In both markets, different auction methods are used, which are examined in more detail. In analysing this case, I put a special focus on the part of the Primary Dealers, which are present in both markets. The Primary Dealers have the exclusive right to participate in the primary market auctions of the government. In contrast, they commit themselves to an active role in the secondary market. This obligation is imposed by the state, who wants to ensure a high level of liquidity in the secondary market with this measure. In the primary market auction, it can be shown that it is optimal for the Primary Dealers, to bid below their maximum willingness to pay. Therefor the state loses auction revenues and the Primary Dealers can reap rents. More competition reduces this behaviour, so the states should be interested in a high number of Primary Dealers in their government bond markets. In the analysis of the secondary market it is shown, how the prices of government bonds are determined. The Primary Dealers have an important function in this market as well, since they act as suppliers of government bonds. In the last part of the thesis, I show the conditions under which a uniform price can arise in the government bond markets of two countries.