In the course of the comprehensive reform of the federal system (Föderalismusreform) which entered into force on 1 September 2oo61, the Federation (Bund) has been granted additional legislative competencies with regard to environmental issues. At the same time, however, the newly established legislative competence of "divergent state legislation" (Abweichungsgesetzgebung) allows the Federal States (Leinder) to enact laws deviating from federal legislation in certain areas. On the one hand, the strengthening of legislative competencies of the Federation with regard to environmental issues enables the enactment of a Federal Environmental Code, which has been under discussion for many years. On the other hand, deviating provisions of the Federal States could undermine the integrative effects of such a code. However, the vast majority of national environmental regulations are mandatory implementation of European law. Thus, the question arises whether the new legislative competence of "divergent state legislation" will even become relevant in practice and whether it will actually impede an integrative Federal Environmental Code, or if the duty to observe European law will serve as a corrective influence and prevent the Federal States from undermining a Federal Environmental Code by precluding them from making extensive use of their powers to enact divergent legislation.