Apart from merger control, the control of abusive practices by dominant companies and providing legal protection in award procedures for public contracts, enforcing the ban on cartels is another task of the Bundeskartellamt and the competition authorities of the Länder and has been an integral element of Section 1 of the Act Against Restraints of Competition (ARC) since the Act came into force in 1958. In the case of cross-border cartels European competition law provides for a ban on cartels in Article 81 of the EC Treaty. In principle, the Bundeskartellamt and the competition authorities of the Länder can also apply the provisions of the European ban on cartels.
If a cartel has a substantial effect on competition in several Member States of the European Union, it will generally be prosecuted by the European Commission. However, if a restraint of competition has its focus in a certain Member State of the European Union, it will be prosecuted by the national competition authorities.
Whether the Bundeskartellamt or the relevant Land competition authority is responsible for enforcing the ban on cartels within Germany generally depends on whether the effect of a competition restraint extends beyond the territory of a federal Land (in this case the Bundeskartellamt is generally the competent authority) or not (in this case the competition authorities of the Länder are generally responsible).

