Case C-24/17: Judgment of the Court (First Chamber) of 8 May 2019 (request for a preliminary ruling from the Oberster Gerichtshof — Austria) — Österreichischer Gewerkschaftsbund, Gewerkschaft Öffentlicher Dienst v Republik Österreich (Reference for a preliminary ruling — Social policy — Prohibition of all discrimination on grounds of age — Directive 2000/78/EC — Exclusion of professional experience obtained before the age of 18 — New system of remuneration and advancement — Maintenance of the difference in treatment — Freedom of movement for workers — Article 45 TFEU — Regulation (EU) No 492/2011 — Article 7(1) — National legislation providing for account to be taken of a proportion of previous periods of service)