Case C-214/20: Judgment of the Court (Fifth Chamber) of 11 November 2021 (request for a preliminary ruling from the Labour Court, Ireland — Ireland) — MG v Dublin City Council (Reference for a preliminary ruling — Protection of the safety and health of workers — Organisation of working time — Directive 2003/88/EC — Article 2 — Concept of ‘working time’ — Retained firefighter — Stand-by time according to a stand-by system — Pursuit, during the period of stand-by time, of a self-employed professional activity — Constraints arising from the stand-by system)