Finally, and technically outside the Copenhagen criteria, comes the further requirement that all prospective members must enact legislation to bring their laws into line with the body of European law built up over the history of the Union, known as the acquis communautaire.
Terakhir, dan secara teknis di luar kriteria Kopenhagen, ada persyaratan lanjutan bahwa semua anggota prospektif harus memberlakukan undang-undang agar hukum mereka sejajar dengan badan hukum Eropa yang dikembangkan sepanjang sejarah Uni, yang dikenal sebagai acquis communautaire.