For European property lawyers, property is the law of things and this has been so for the past centuries. In this perspective, property law focuses on transactions of these things and is therefore transactional law. Increasingly there is a number of lawyers that considers property in a constitutional context. However, this is mostly done at a national level, or by comparing national constitutional property law, usually constitutional property provisions, to other countries. Constitutional property, I submit, is much more than just the national constitutional provision, and concerns the way in which property is to be understood, organised and applied in a legal order.In the EU legal order, which has a single or internal market, which is more than a mere sum of its components, there is a great need to rethink the position of property. The EU internal market is a social market economy to which fundamental principles of property law (freedom of ownership, free circulation of goods and freedom of contract) are inextricably linked. A change away from the market economy will bring great difficulties in the current composition of the EU legal order, as too many aspects are dealt with at the national level. The EU legal order relies heavily on the existence of these fundamental principles of property law in the systems of the Member States that ‘upload’ these to the EU level. EU economic constitutional law as well as EU social constitutional law can provide guidance for the development of EU (constitutional) property law. There is - borrowing from the South African experience - an algorithm for the development of property law in the EU, in which the primacy of regulation is with private parties, followed by the Member States who are all bound by the economic and social context provided for by EU law. That normative framework is not to be followed voluntarily, but comes with the method and thus with the force of supranational EU law, including direct effect, effet utile, and the principle of sincere cooperation between Member States. This is all balanced by the principles of subsidiarity and proportionality that keep the EU out of matters it should not concern itself with.