Case C-35/20: Judgment of the Court (Fifth Chamber) of 6 October 2021 (request for a preliminary ruling from the Korkein oikeus — Finland) — Criminal proceedings against A (Reference for a preliminary ruling — Citizenship of the Union — Right of Union citizens to move freely within the territories 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 moving between Member States without an identity card or 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)