Rules on evidence & their applicability to ‘old’ contracts

Book 8 of the new Belgian Civil Code (CC) was the first one of the new CC to be approved. It entered into force on November 1st, 2020, introducing a new set of rules on evidence. An important question is how these rules apply to contracts concluded before then. We listed what you should remember and which considerations you should make.


Usually, statutory dispositions such as Book 8 are accompanied by transitional rules. These aim to clarify when these dispositions enter into force and how they will affect already existing contracts and proceedings. Unfortunately, such transitional rules are not at hand for Book 8. According to the explanatory memorandum, the “old” rules on evidence must be applied to such existing contracts. However, the Council of State is of the opinion that the “new” rules are applicable to these “old” contracts as well.



The Belgian Supreme Court tried to solve the matter with its judgment of February 4th, 2021. It asserted that the admissibility of evidence depends on the rules on evidence that were applicable at the time of the conclusion of the contract. The transitional rules are then as follows:


  • The rules on the burden of proof contained in Book 8 CC will apply immediately to all contracts and proceedings. Note that these are the rules on who needs to deliver the proof, and to which degree of certainty.
  • All other rules on evidence in Book 8 will only apply to contracts celebrated after November 1st, 2020, and related proceedings. For example, the principle that all evidence between enterprises is free.
  • For “old” contracts or recent proceedings regarding such contracts, the old rules are still applicable.

However, not all courts agree with this transitional system. In March 2022, for example, the court in Oudenaarde applied the new rules of Book 8 (other than the burden of proof) on a contract concluded before November 1st, 2020.


By not including a transitional system, the legal certainty of the new rules is diminished. Even though the verdict of the Court of Oudenaarde does not seem very popular, today it remains very hard for parties to estimate which evidentiary rules shall apply to their “old” contracts.


To be continued…


Laura Van Gompel



Laura Van Gompel

Lawyer – Managing Partner


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