All approvals must comply with the national law of Denmark and Germany, and relevant EU directives must be followed. The public of both nations are also involved in the approval process, for example in consultations regarding environmental aspects.
The effects of an infrastructure project on this large scale reach well beyond Denmark’s and Germany’s borders. This is the case for environmental impacts, such as total carbon emissions. Shipping traffic is also affected. This is why a number of international laws and conventions have to be taken into account in approval of the project.