Judgment of the Court (Sixth Chamber) of 3 July 2001 in Case C-378/98: Commission of the European Communities v Kingdom of Belgium (Failure by a Member State to fulfil its obligations — State aid — Article 93(2), second subparagraph, of the EC Treaty (now Article 88(2), second subparagraph, EC) — Obligation to recover aid granted under the Maribel bis and Maribel ter schemes — Impossible to put into effect)