Case T-754/17: Judgment of the General Court of 30 April 2019 — Chambre de commerce et d’industrie métropolitaine Bretagne-Ouest (port de Brest) v Commission (State aid — General corporate tax exemption scheme implemented by France in favour of its ports — Decision declaring the aid scheme incompatible with the internal market — Existing aid — Concept of economic activity — Services of general interest — Principle of sound administration — Duty to state reasons — Error of assessment)