## Facts

- The cases arose from proceedings before the French Conseil Constitutionnel concerning the legality of national legislation implementing an EU Directive.
- The Conseil Constitutionnel maintained its jurisdiction to review the constitutionality of domestic measures implementing EU law within the French legal system.
- Mr. Melki and Mr. Abdeli challenged this stance, arguing it threatened the supremacy of EU law.
- The matter was referred to the Court of Justice of the European Union (CJEU) to address the compatibility of the French constitutional review process with the principle of EU law primacy.

## Issues

1. Whether national constitutional courts can review and potentially override national measures implementing EU law on the basis of domestic constitutional provisions.
2. Whether the French constitutional review process risks undermining the uniformity and effectiveness of EU law.
3. Whether the preliminary ruling procedure under Article 267 TFEU suffices to resolve conflicts between national constitutional law and EU law.

## Decision

- The CJEU confirmed the priority of EU law over national constitutional law in areas of EU competence.
- The Court held that national courts, including constitutional courts, must not declare national measures implementing EU law invalid on constitutional grounds without first referring questions of EU law interpretation or validity to the CJEU under Article 267 TFEU.
- The judgment clarified that adherence to the preliminary ruling procedure is essential to maintain the coherence of the EU legal order.
- The CJEU rejected the argument that national constitutional provisions could be used to disregard EU law, reinforcing the binding nature of EU law on all member states.

## Legal Principles

- The primacy of EU law obliges member states, including national constitutional authorities, to give effect to EU norms even over conflicting national constitutional provisions.
- The preliminary ruling procedure under Article 267 TFEU is the proper mechanism for resolving uncertainties concerning EU law, ensuring its uniform interpretation and application.
- Membership in the European Union entails an obligation to accept the supremacy of EU law in areas of EU competence, limiting national sovereignty accordingly.

## Conclusion

The CJEU’s decision in Melki and Abdeli decisively affirmed that EU law takes precedence over conflicting national constitutional rules and made clear that the preliminary ruling procedure is indispensable for resolving possible conflicts, thereby safeguarding the effectiveness and uniformity of EU law across member states.

Melki and Abdeli (Joined Cases C-188/10 and C-189/10) [2010] ECR I-5667