Judgment of the Court (Eighth Chamber) of 13 July 2023.#Achilleion Anomymi Xenodocheiaki Etaireia v Elliniko Dimosio.#Reference for a preliminary ruling – Structural Funds – European Regional Development Fund (ERDF) – Co-financing – Regulation (EC) No 1260/1999 – Articles 30(4) and 39(1) – Durability of investment operations – ‘Substantial modification’ of a co-financed investment operation – Recovery of aid in the event of transfer of the establishment which is the subject of that operation – Effect of the specific circumstances surrounding that transfer.#Case C-313/22.