Judgment of the General Court (Tenth Chamber, Extended Composition) of 20 December 2023.#Autorità di sistema portuale del Mar Ligure occidentale and Others v European Commission.#State aid – Taxation of port authorities in Italy – Exemption from corporate income tax – Decision declaring aid incompatible with the internal market – Existing aid – Concept of ‘undertaking’ – Concept of ‘economic activity’ – Advantage – Selectivity – Distortion of competition – Effect on trade between Member States – Equal treatment.#Case T-166/21.