Case C-710/18: Judgment of the Court (Seventh Chamber) of 23 April 2020 (request for a preliminary ruling from the Bundesarbeitsgericht — Germany) — WN v Land Niedersachsen (Reference for a preliminary ruling — Freedom of movement for workers — Article 45(1) TFEU — Remuneration — Step allocation in a remuneration system — Remuneration system linking entitlement to a higher remuneration rate to length of service with the same employer — Limitation of the account to be taken of previous periods of relevant activity with an employer in a Member State other than the Member State of origin)