Case C-672/13: Judgment of the Court (Sixth Chamber) of 19 March 2015 (request for a preliminary ruling from the Fővárosi Törvényszék — Hungary) — OTP Bank Nyrt v Magyar Állam, Magyar Államkincstár (Reference for a preliminary ruling — State aid — Article 107(1) TFEU — Concept of ‘State aid’ — Housing aid granted prior to the accession of Hungary to the European Union to certain categories of household — Payment of the aid by credit institutions in exchange for a State guarantee — Article 108(3) TFEU — Measure not previously notified to the European Commission — Unlawfulness)