Where, in insolvency proceedings, a payment made by a third party in performance of a contracting party's payment obligation is challenged as detrimental to all creditors, the law governing the contract under Regulation No 593/2008 also governs that payment.

1. Article 13 of Council Regulation (EC) No 1346/2000 of 29 May 2000 on insolvency proceedings must be interpreted to the effect that the form and the time-limit in which a person benefiting from an act that is detrimental to all the creditors must raise an objection under that article, in order to challenge an action to have that act set aside in accordance with the lex fori concursus, and the question whether that article may also be applied by the competent court of its own motion, if necessary, after the time-limit allowed to the party concerned has expired, fall within the procedural law of the Member State on whose territory the dispute is pending. That law must not, however, be less favourable than the law governing similar domestic situations (principle of equivalence) and must not make it excessively difficult or impossible in practice to exercise the rights conferred by EU law (principle of effectiveness), that being a matter for the referring court to determine.

2. Article 13 of Regulation No 1346/2000 must be interpreted to the effect that the party bearing the burden of proof must show that, where the lex causae makes it possible to challenge an act regarded as being detrimental, the conditions to be met in order for that challenge to be upheld, which differ from those of the lex fori concursus, have not actually been fulfilled.

3. Article 13 of Regulation No 1346/2000 may be validly relied upon where the parties to a contract, who have their head offices in a single Member State on whose territory all the other elements relevant to the situation in question are located, have designated the law of another Member State as the law applicable to that contract, provided that those parties did not choose that law for abusive or fraudulent ends, that being a matter for the referring court to determine.