Case C-482/17: Judgment of the Court (Grand Chamber) of 3 December 2019 — Czech Republic v European Parliament, Council of the European Union (Action for annulment — Approximation of laws — Directive (EU) 2017/853 — Control of the acquisition and possession of weapons — Validity — Legal basis — Article 114 TFEU — Amendment of an existing directive — Principle of proportionality — Absence of impact assessment — Interference with the right to property — Proportionality of the measures adopted — Measures creating barriers in the internal market — Principle of legal certainty — Principle of the protection of legitimate expectations — Measures obliging Member States to adopt legislation with retroactive effect — Principle of non-discrimination — Derogation for the Swiss Confederation — Discrimination affecting Member States of the European Union or Member States of the European Free Trade Association (EFTA) other than that State)