The Court of Justice of the European Union ruled on a case concerning the principle of lex mitior

On 1 August 2025, the Grand Chamber of the CJEU, in Case No. C-544/23 (BAJI Trans), delivered a judgment on a preliminary question referred by the Grand Chamber of the Supreme Administrative Court of the Slovak Republic concerning the interpretation of the scope and application of the lex mitior principle. The CJEU examined whether, in proceedings concerning an extraordinary domestic remedy (cassation appeal), the Supreme Administrative Court is obliged to take into account a change in the legal framework in favor of the offender after the decision of the lower administrative court has been issued.

By a decision dated 16 August 2023, the Grand Chamber of the Supreme Administrative Court referred preliminary questions to the Court of Justice of the European Union (CJEU) concerning the interpretation of the Charter of Fundamental Rights of the European Union—specifically regarding both its scope and the substantive interpretation of the lex mitior principle contained therein. The case involved assessing whether the panel of the cassation court is obliged to take into account a change in the legal framework in favor of the offender that occurred during the cassation proceedings and after the decision of the lower administrative court had been issued.
(More information was provided in the press release Court of Justice of the European Union to rule on lex mitior case in Grand Panel – Najvyšší správny súd Slovenskej republiky)

The Grand Chamber of CJEU ruled:

1. Article 51(1) of the Charter of Fundamental Rights of the European Union must be interpreted as meaning that a Member State is implementing Union law for the purposes of that provision when (i) in accordance with Article 19(1) of Council Regulation (EEC) No 3821/85 of 20 December 1985 on recording equipment in road transport, as amended by Regulation (EC) No 561/2006 of the European Parliament and of the Council of 15 March 2006, and Article 41(1) of Regulation (EU) No 165/2014 of the European Parliament and of the Council of 4 February 2014 on tachographs in road transport, repealing Council Regulation (EEC) No 3821/85 on recording equipment in road transport and amending Regulation (EC) No 561/2006 of the European Parliament and of the Council on the harmonisation of certain social legislation relating to road transport, it imposes an administrative penalty on the driver of a vehicle because of a failure, by that driver, to fulfil obligations laid down by those regulations and (ii) it subsequently avails itself of the possibility which it is recognised as having under Article 3(2) of Regulation No 165/2014 of exempting certain road transport vehicles from having to comply with such obligations.
2. The last sentence of Article 49(1) of the Charter of Fundamental Rights must be interpreted as meaning that it is capable of being applied to an administrative penalty of a criminal nature which has been imposed on the basis of a rule which, after the imposition of the penalty, has been amended in a way which is more favourable to the person concerned by that penalty, provided that that amendment reflects a change of position regarding the criminal classification of the acts committed by that person or regarding the penalty to be applied.
3. The last sentence of Article 49(1) of the Charter of Fundamental Rights must be interpreted as meaning that a court hearing an appeal in cassation against a judicial decision dismissing the action brought against an administrative fine of a criminal nature and falling within the scope of EU law is, in principle, required to apply a piece of national legislation which is more favourable to the convicted person and which entered into force after the delivery of that judicial decision, irrespective of whether that decision is regarded as final under national law.

In its press release, the CJEU states: “Hearing questions from the Slovak Supreme Administrative Court, the Court of Justice provides important clarifications concerning the principle of lex posterior mitius laid down by the Charter of Fundamental Rights of the European Union (‘the Charter’) (which applies in all cases where Union law is being implemented by a national authority). Although that principle is reserved for the field of criminal law, the classification of a penalty as administrative under national law does not necessarily preclude the application of that principle. Indeed, it may be the case that, under EU law and with the aim of guaranteeing a uniform application of that principle, an administrative penalty must be regarded as criminal owing to the intrinsic nature of the offence and the degree of severity of the penalty. Furthermore, that principle applies so long as the conviction has not become final. What must or must not be regarded as a final ruling, in that context, is also delimited by EU law. The mere fact that a conviction decision is classified as final under national law when it may be the subject of an appeal in cassation is not sufficient reason to disapply that principle.”

The full text of the CJEU press release: The principle of lex posterior mitius extends to a penalty classified as administrative under national law where it is of a criminal nature for the purposes of EU law.

The full text of the CJEU judgment: EUR-Lex – 62023CJ0544 – EN – EUR-Lex