The article reveals how the patterning of European affairs in the Assemblée Nationale and the Bundestag goes hand in hand with a divergence in the logic motivating the reforms of each chamber’s formal frameworks for EU participation. While early reforms were the fruit of a great variety of ideological or power battles in both parliaments, reforms after the significant increase in EU decision making in the 1990s correspond to different domestic roles played by MPs. This observation can be understood through the emergence of ‘typical’ change agents sharing ‘typical’ motives about necessary reforms across party lines in both chambers.