The paper at hand analyzes Case C-349/17 – Eesti Pagar as a landmark decision in the development of the Court of Justice of the European Union’s case law on the decentralized enforcement of State aid rules. Through this judgment, the CJEU reaffirmed the essential institutional role of national courts in ensuring compliance with Article 108(3) TFEU, highlighting their duty to assess ex officio the legality of public support measures, t...