Case C-122/15: Judgment of the Court (First Chamber) of 2 June 2016 (reqeust for a preliminary ruling from the Korkein hallinto-oikeus — Finland) — proceedings brought by C (Reference for a preliminary ruling — Social policy — Principles of equal treatment and non-discrimination on grounds of age — Directive 2000/78/EC — Equal treatment in employment and occupation — Articles 2, 3 and 6 — Difference in treatment on grounds of age — National legislation providing, in certain situations, for higher taxation of pension income than earned income — Scope of application of Directive 2000/78 — Competence of the European Union in the field of direct taxation)