The condictio indebiti is an action in civil (Roman) law whereby a plaintiff may recover what he has paid the defendant by mistake; such mistaken payment is known as solutio indebiti.
This action does not lie The action is extant in civil (Roman) or hybrid law regimes, e.g. Norway,[4] South Africa and Scotland .
[5] § 812 I 1 1.
Alt BGB (German Civil Code)