French coalition politics is distinctive in Western Europe. There is a strongly imbalanced power structures in favour of the party of the President (or Prime Minister in times of cohabitation). France is therefore a particular and rather extreme case of dominant Prime Minister Model. The constitution of the Fifth Republic creates strong incentives to build pre-electoral alliances, but the majoritarian electoral system and semi-presidentialism have led to an extreme predominance by the main parties, and in particular of the chief of the executive, over their junior partners. Institutional reforms have still reinforced the weight of president. Small parties can exert leverage mainly before the elections, given their capacity to negotiate their support during the campaign and mutual withdrawals for the first or the second round of elections. Once the election is passed, coalition politics are strongly structured by presidential logics (outside cohabitations) and take place to a large extent beyond parties: individual MPs from the same party may join different parliamentary groups depending on their attitude towards the president. Given the absence of formal coalition governance arrangements, junior parties’ resources for influencing government policies are very much restricted to public communication, informal exchanges with the chief of the executive, and the threat to leave the coalition. Modalities of coalition governance provide the chief of the executive (i.e. the president since 2002) with strong leadership, extensive leverage in policymaking and a final say in interministerial disputes. He usually manages to get his way and only rarely consult parties in his coalition. Consequently, these parties will affect policy outcomes only with respect to very emblematic issues (usually one or two) and to the definition of “red lines” likely to be a motivation for terminating their participation to government. Political parties are aware of this and do not expect coalition agreements to be implemented – they conceive them at best as a document allowing them to present their agreement as a political project and not as a mere electoral alliance. This situation nourishes considerable frustration within most junior coalition parties.