Abstract: The Treaty establishing the European Community (and its successor, the Functioning of the European Union (FEU) Treaty) nearly exclusively contains rules of a public law character. However, some of its central provisions have also acquired significance for private law, because the Court of Justice has interpreted them in such a way that they have become directly applicable to relationships between individuals, in the sense that they create subjective rights and obligations between them. Put in another way, those provisions now produce a direct horizontal effect in private law relationships. Direct horizontal effect must be distinguished from indirect horizontal effect. Unfortunately, in legal literature, these concepts do not have a clear and commonly accepted meaning. This article tries to bring some clarity by proposing a specific definition of horizontal direct effect and explaining the differences with some other types of effect in relationships between individuals, in particular the review (in disputes between individuals) of the compatibility of national legislation with EU law, the concept of ‘positive obligations’, and the concept of harmonious interpretation. The discussion takes place against the background of some well-known cases, such as Defrenne, Walrave, Delhaize, Schmidberger, and (AG Poiares Maduro’s opinion in) Viking.
European Review of Private Law