Case C-202/20 P: Judgment of the Court (Eighth Chamber) of 12 May 2021 — Claudio Necci v European Commission, European Parliament, Council of the European Union (Appeal — Civil service — Former member of the contract staff — Social security — Joint Sickness Insurance Scheme (JSIS) — Article 95 of the Conditions of Employment of Other Servants of the European Union (CEOS) — Continued membership after retirement — Condition of having been employed for more than three years — Request to join the JSIS following a transfer of pension rights — Equating the credited years of pensionable service with years of service — Rejection of the request — Action for annulment — Act having an adverse effect — Order of the General Court declaring the action inadmissible — Order set aside)