Unlike the United States with its three-tiered federal judiciary, the European Union does not have a full-fledged court system of its own. In most cases, there is but a single instance with a limited number of available types of procedure. Private parties who want to file an action and claim the rights conferred by EU law against other private persons cannot file an action with a court of the Union; they must seek the remedy in the national courts of a Member State. The only institutional connection of the many national judicial systems is the Court of Justice of the European Union. At least in theory, there is a mechanism for the enforcement of EU rights in this Court.

The Court is unique in its role for private law. While many instruments on uniform private law have been adopted ever since the second half of the 19th century, their interpretation has nearly always remained in the hands of the national judiciaries and has almost never been entrusted to an international institution. Although modern Conventions usually lay down a duty to seek a uniform application, and scholars and international organisations have made the divergence of legal practice has surfaced time and again; it appears inevitable in the absence of a procedural mechanism that allows the overcoming of differences by authoritative decisions. For the first time in the history of private law, the Court of Justice offers the opportunity to stop the disintegration of uniform law in the course of its application.

This part will present the Court of Justice in a first chapter, see Chapter XXXI. Its function and operation should not be mixed up with that of an appeal court. Only some peculiar types of procedure are available for EU private law, the most important being the referral procedure under Article 267 TFEU which deserves and receives closer scrutiny in Chapter XXXII below. But in general, there is no way for a private party to take a case to the Court of Justice on his or her own initiative, not even where the infringement of a fundamental right or a human right is at issue.