Case C-424/09: Judgment of the Court (Grand Chamber) of 5 April 2011 (reference for a preliminary ruling from the Symvoulio tis Epikratias (Greece)) — Christina Ioanni Toki v Ipourgos Ethnikis Pedias Thriskevmaton (Directive 89/48/EEC — Points (a) and (b) of the first subparagraph of Article 3 — Recognition of higher education diplomas — Environmental engineer — Activity deemed to be a regulated professional activity — Applicable mechanism of recognition — Meaning of ‘professional experience’ )