The EU has added FAQ 13 to its import, purchase & transfer of listed goods Russia sanctions FAQs, which asks:
Can Russian nationals temporarily bring personal goods and vehicles listed in Annex XXI and subject to the prohibition in Art. 3i of Council Regulation 833/2014 into the Union, e.g. for touristic travels?
No. Article 3i of Council Regulation 833/2014 prohibits the purchase, import, or transfer, directly or indirectly, of goods as listed in Annex XXI to the Regulation if they originate in Russia or are exported from Russia. This includes motor vehicles (cars) falling under CN code 8703.
A limited exemption exists for the purchase of goods in Russia for the personal use of nationals of Member States and their immediate family members (see Article 3i paragraph 3a). Besides the already expired transitional period, no further exceptions are foreseen and the import of such goods from Russia is prohibited.
It is not relevant whether the use of the vehicles is private or commercial as long as the vehicles are falling under a CN code listed in Annex XXI (e.g. CN code 8703) and are originating in or are being exported from Russia. This is most likely the case for vehicles having a Russian license plate and are registered in Russia. The duration of their possible stay in the Union and respectively the customs procedures under which they will be placed (e.g. release for free circulation or temporary admission) is also not relevant.