The Engie decision of the General Court of 12 May 2021 has added a new dimension to the Union law prohibition of State aid: It can act as a pervasive substance over form doctrine without the limitation to “wholly artificial arrangements” inherent to conventional anti-abuse rules and principles of Union law. Art. 107 (1) TFEU has thus potentially become the capstone of the European anti-avoidance architecture. And while it would not come as a surprise if Engie or Luxembourg appealed the judgement, it is far from certain that the Court of Justice of the EU (CJEU) would annul it, because the General Court’s rationale is indeed well-founded in the expansionist tendencies of fiscal State aid jurisprudence of the CJEU. This short paper explores the key findings of the Court, and analyses how CJEU case law has paved the way for a “State aid GAAR”, where the Court could or should have decided differently, and the overall implications of the Engie judgement.