Abstract: EU law is a fact in private law. The influence of EU law in private law and horizontal relationships creates an incentive for actors to rely on that influence, both to invoke a right granted by EU law, to construe arguments and to elaborate creatively on existing possibilities. Therefore private law and horizontal relationships are of relevance for EU law.
To enable actors to clearly understand the law governing horizontal relationships, to weigh and balance the aims of both fields of law, and develop arguments, this contribution presents an approach taking into account the mutual dependence of EU and private law and consequently the need for exchange between both fields of law. The approach combines a top-down analysis of the effectuation of EU law in horizontal relationships (starting from the supremacy and direct effect of EU law) with a bottom-up approach taking into account the concrete horizontal relationship. To enable substantive guidance on the interaction between EU and private law the aims, requirements, possibilities and limitations which follow both from EU and private law are linked to principles used in EU and private law.
In this vein, the EU's Charter of Fundamental Rights has an important role to play. The Charter can be used to translate a private law principle into a principle that is recognized under EU law. It is for this reason that the Charter, which owes its existence to brilliant sources of inspiration mainly outside private law, has a promising future in private law.European Review of Private Law