Judgment of the Court (Fifth Chamber) of 6 October 2021.#Criminal proceedings against A.#Reference for a preliminary ruling – Citizenship of the Union – Right of Union citizens to move freely within the territory of the Member States – Article 21 TFEU – Directive 2004/38/EC – Articles 4 and 5 – Obligation to carry an identity card or a passport – Regulation (EC) No 562/2006 (Schengen Borders Code) – Annex VI – Crossing the maritime border of a Member State on board a pleasure boat – Rules on sanctions applicable when travelling between Member States without an identity card or a passport – Rules on daily fines in criminal cases – Calculation of the fine based on the offender’s average monthly income – Proportionality – Severity of the sanction in relation to the offence.#Case C-35/20.