If you read English:
Who has the competence to negotiate an exit treaty if one Member State decides to withdraw from the EU – the remaining Member States, the EU or both? Art. 50 of the Treaty on European Union lays down a basic roadmap of the actions which have to be taken in case of an exit and determines that the exit treaty should set out the arrangement for both the withdrawal and the framework for the future relationship between the leaving Member State and the EU. However, the provision does not spell out whether the EU is allowed to conclude the exit treaty without the consent of the remaining Member States. Such a consent is of particular importance when it comes to the future relationship of the EU and the leaving Member States.
Caroline Heber points out that the existence of secondary EU law plays a crucial role when it comes to deciding whether or not the Member States have to be granted the right to participate in the negotiation process. In the light of competence to negotiate the exit treaty, existing secondary law can be divided into several categories. Only secondary EU law which has a nexus to states outside the EU or achieves a full harmonisation transfers the competence to the EU, and thus allows the European Institutions to negotiate the exit treaty without any participation of the remaining Member States.
Other forms of secondary EU law do not grant the EU an exclusive competence in the negotiation process. Accordingly, in these fields the remaining Member States cannot be excluded from the negotiation process.
Veröffentlichung: Europarecht, 2017, Vol. 52, No. 5, 581–659