Het in pari-beginsel: Nederland versus België

This article is about the Latin adage: "In pari delicto potior est condicio defendentis' ('In the case of equal wrongfulness the defendant has a stronger right'). It provides an exception to the main rule of (Dutch) restitution law, namely that when a payment is without any legal basis, this payment can be claimed back. According to Roman Law the scope of the in pari-exception was small. But, the Dutch Hoge Raad doesn't accept the in pari-rule at all, even not for reasons of reasonableness and fairness. In the 1930's this was discussed extensively in legal literature. The majority of the jurists believed that the in pari-adage must be rejected. This makes the Netherlands an exception in Europe.
In my opinion the arguments for the rejection are not convincing. It is strange that, according to Dutch restitution law, in the context of reasonableness and fairness anything but the in pari-adage can be taken into consideration. I think that the Dutch judge can learn a lot from his Belgian colleague. In Belgium, the application of the in pari-adage isn't forbidden, but is left to the lower courts.