The fact that the order for reference concerning the interpretation of a convention adopted on the basis of Title VI of the EU Treaty, in the version applicable prior to the entry into force of the Treaty of Lisbon, does not mention Article 35 EU but rather refers to Article 267 TFEU cannot of itself render the reference for a preliminary ruling inadmissible.

Article 54 of the Convention Implementing the Schengen Agreement (CISA), which makes the application of the ne bis in idem principle subject to the condition that, upon conviction and sentencing, the penalty imposed ‘has been enforced’ or is ‘actually in the process of being enforced’, is compatible with Article 50 of the Charter of Fundamental Rights of the European Union, in which that principle is enshrined.

The additional condition laid down in Article 54 CISA constitutes a limitation of the ne bis in idem principle that is compatible with Article 50 of the Charter, since that limitation is covered by the explanations relating to the Charter as regards Article 50 of the Charter which are directly referred to in the third subparagraph of Article 6(1) TEU and Article 52(7) of the Charter.

In any event, the execution condition which subjects the more extensive protection offered by Article 50 to an additional condition constitutes a limitation of the right enshrined in that article within the meaning of Article 52 of the Charter.

In the first place, the limitation of the ne bis in idem principle must be considered as being provided for by law, since it arises from Article 54 CISA.

In the second place, a provision such as Article 54 CISA must be regarded as respecting the essence of the ne bis in idem principle. The execution condition laid down in that provision does not call into question the ne bis in idem principle as such, since it is intended to avoid a situation in which a person definitively convicted and sentenced in one Contracting State can no longer be prosecuted for the same acts in another Contracting State and therefore ultimately remains unpunished if the first State did not execute the sentence imposed.

In the third place, as can be seen from Article 67(3) TFEU, in order to achieve its objective of constituting an area of freedom, security and justice, the European Union endeavours to ensure a high level of security through measures to prevent and combat crime, and through measures for coordination and cooperation between police and judicial authorities and other competent authorities, as well as through the mutual recognition of judgments in criminal matters and, if necessary, through the approximation of criminal laws. The execution condition laid down in Article 54 CISA is to be seen in that context since it is intended to prevent, in the area of freedom, security and justice, the impunity of persons definitively convicted and sentenced in an EU Member State. Moreover, the execution condition is appropriate for attaining the objective pursued, since by allowing, in cases of non-execution of the sentence imposed, the authorities of one Contracting State to prosecute a person definitively convicted and sentenced by another Contracting State on the basis of the same acts, the risk that the person concerned would enjoy impunity by virtue of his leaving the territory of the State in which he was sentenced is avoided. As to whether the execution condition is necessary, while there are numerous instruments of secondary legislation at the EU level intended to facilitate cooperation between the Member States in criminal law matters, such instruments of mutual assistance do not lay down an execution condition similar to that of Article 54 CISA and, accordingly, are not capable of fully achieving the objective pursued. However, in the application in concreto of the execution condition laid down in Article 54 CISA in a given case, it cannot be excluded that the competent national courts may — on the basis of Article 4(3) TEU and the abovementioned instruments of secondary legislation — contact each other and initiate consultations in order to verify whether the Member State which imposed the first sentence really intends to execute the penalties imposed.

(see paras 55, 57-59, 62-65, 68, 73, 74, operative part 1)