Case C-168/18: Judgment of the Court (Fifth Chamber) of 19 December 2019 (request for a preliminary ruling from the Bundesarbeitsgericht — Germany) — Pensions-Sicherungs-Verein VVaG v Günther Bauer (Reference for a preliminary ruling — Social policy — Protection of employees in the event of the insolvency of their employer — Directive 2008/94/EC — Article 8 — Supplementary pension schemes — Protection of entitlement to old-age benefits — Minimum guaranteed level of protection — Former employer’s obligation to offset a reduction in an occupational old-age pension — External pension institution — Direct effect)