Case C-236/18: Judgment of the Court (Second Chamber) of 19 December 2019 (request for a preliminary ruling from the Cour de cassation — France) — GRDF SA v Eni Gas & Power France SA, Direct énergie, Commission de régulation de l’énergie, Procureur général at the Cour d’appel de Paris (Reference for a preliminary ruling — Common rules for the internal market in natural gas — Directive 2009/73/EC — Article 41(11) — Settlement of disputes concerning the obligations imposed on a system operator — Temporal effects of decisions of the dispute settlement authority — Legal certainty — Legitimate expectations)