Respective roles of EU and national law

Chapter 4 is set in the EU multi-layered legal system, where questions concerning the tracing of the frontier between EU law and national law are common. This chapter notes that private enforcement of EU competition law before the national courts is a good example of the multifarious interplay between EU law and national law. This is because the right to compensation results directly from the Treaty provisions, whereas the enforcement of such actions before the national courts takes place according to national law as shaped by the principles of equivalence and effectiveness and, now, the rules of the Antitrust Damages Directive. However, despite the illusive clarity of the division thus established, the question arises anew in each case as to which issues of an antitrust damages action fall specifically under EU law and which issues of such an action are governed by the national law of the Member States. The chapter outlines, first, how the frontier between EU law and national law in the field of private enforcement of EU competition law runs along a demarcation line between substantive claim and procedural enforcement. Second, it illustrates, on the basis of examples from the jurisprudence of the Court, the concrete expressions of this demarcation line as regards the application of the conditions for antitrust liability and damage compensation under Articles 101 and 102 TFEU.