The Council of the European Union Regulation for protecting against the effects of the extra-territorial application of legislation adopted by a third country, and actions based thereon or resulting there from.
Following the illegal departure of the USA from the 2015 agreement with Iran known as the Joint Comprehensive Plan of Action (JCPOA), the European Union updated an EU legislation called Blocking Statute which had originally been issued on 22 November 1996.
According to the Blocking Statute, the EU member states are required to take necessary measures to deal with the imposition of US unilateral and extra-territorial sanctions on third countries in order to support and protect European companies.
Article 5 of the Blocking Statute provides the legal basis for penalizing those who abide by the American Sanctions Act against Iran. According to the provisions of this article, in the event of any European firm or company refusing to implement the Blocking Statute by following American extra-territorial legislations, EU member states are obliged to penalize those entities at the national level.
Furthermore, according to Article 9, each member state of the European Union will determine the nature of the penalties that should be imposed in the case of violations of this law. The enforcement of the law will be undertaken by EU member states and it should be implemented at national level.
The following link contains further information:
https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:31996R2271&from=EN