When companies act in violation of antitrust law, they harm consumers. These consumers are entitled to damages to compensation, but they often do not enforce them due to a rational lack of interest. Johanna Schoning investigates if the new German model declaratory action ("Musterfeststellungsklage") facilitates the enforcement of antitrust damage claims and whether the action strenghens private enforcement of antitrust law. First of all, there is a need for model declarations ("Musterfeststellungen") in addition to the binding effect of decisions of the cartel authorities. Furthermore, there are many particularities that the parties to an antitrust declaratory action must take into account. In particular, the jurisdiction, the declaratory judgement objectives, multi-person constellations, settlements, cost issues and the relationship to leniency programes are important. All this is covered in the work, including relations to international law.