The Court of Justice confirmed the obligation for a national judge to order the payment of illegality interest also where the aid, implemented in breach of Article 108(3) TFEU, has been declared by the Commission compatible with the internal market under Article 106(2) TFEU. By extending the findings in CELF to illegal State aid granted in favour of undertaking entrusted with the operation of services of general economic interest, the Court has clarified that the performance of SGEI tasks cannot, in and of itself, justify an exemption from the notification and standstill requirements under Article 108(3) TFEU.