This article addresses the distribution of accountability between the European Union (EU) and its Member States under the current and future climate regime. Belonging to a field of shared competence between the EU and its Member States, the climate regime is characterized by ‘mixed agreements’, not distinguishing between the obligations of the EU and its Member States. This raises the question of how to determine who is accountable in case of non-compliance. Under the current regime, there is a joint and proportional accountability rule regarding the European common emission reduction target. This rule is well suited to the nature of the EU, and should therefore be maintained in the next climate agreement. For other commitments, third parties, the Secretariat of the Climate Change Convention and the Kyoto Protocol Compliance Committee enjoy a margin of discretion to evaluate whether it is pragmatic to address non-compliance with regard to only the Member State concerned or to involve the EU in the process. This approach, favouring a return to compliance, also appears adapted to the EU. Indeed, an ad hoc intra-European mechanism allows for the identification of the actor actually accountable. To avoid holding the EU as a whole accountable while the entity actually accountable is a Member State or the EU, some intra-European actions for recovery are available to the EU, its Member States and even private persons.