The 2012 votes on the European Fiscal Compact and the European Stability Mechanism enabled a few French and German MPs to contest their party’s position on this matter. We conduct a comparative analysis of the processes which led to these parliamentarians’ opposition and of the consequences of their votes on their political career. We show that these intra-partisan oppositions are focused on different stakes in France and Germany and that, in Germany, partisan discipline led to the control – and in some cases to the exclusion – of dissidents.