Since a ruling of the Mixed Chamber of 28 September 2012, the rule is well known: a judge cannot base a decision exclusively on an expert report commissioned by one party alone. Two recent rulings mark out its limits. The first confirms that the rule applies even to a private appraisal carried out in the presence of the other party, but sets it aside when the fact found is not disputed. The second sets it aside when the expert was chosen by mutual agreement under the contract. For anyone commissioning a valuation for use in litigation, these nuances matter.
The principle
The rule flows from article 16 of the French Code of Civil Procedure, which requires the judge to ensure that the adversarial principle is respected. An appraisal commissioned by one party, outside any court framework, does not give the opponent the safeguards of a court-ordered appraisal (expertise judiciaire), where the expert is appointed by the court, bound to impartiality (article 237) and must take the parties’ observations into account (article 276). A single-party report is admissible as evidence, but it must be corroborated by other elements.
The Charte de l’expertise en évaluation immobilière (the French property valuation charter) in fact distinguishes three formats: the private single-party valuation, where only the client is informed; the joint private valuation, commissioned by two or more parties; and the court-ordered appraisal, on appointment by a judge (6th edition, November 2025, Title I, § 1.1).
First ruling: an appraisal in the presence of the other party remains a party’s appraisal, unless the fact is undisputed
In the sale of a used vehicle, the buyer’s insurer had a private appraisal carried out “in the presence of” the seller, which concluded that the mileage had been altered before the sale. The court rescinded the sale on the strength of that report alone.
The Cour de cassation (the French supreme court for civil and commercial matters) dismissed the appeal (Cass. 1re civ., 15 October 2025, appeal no. 24-15.281, reported decision), but stated a two-part rule: “while the judge cannot base a decision exclusively on a non-judicial expert report, even one drawn up in the presence of the other party, established at the request of one party, it is otherwise if the expert’s findings and conclusions relate to a fact that is established and not disputed by the parties”. In this case, the seller did not dispute the alteration of the mileage; the court could therefore rely on the appraisal.
The lesson is twofold. Inviting the opponent to a private appraisal is not enough, on its own, to give the report the weight of a court-ordered appraisal. But when the facts found are not disputed, the report can found the decision.
Second ruling: the expert chosen by mutual agreement under the contract
Building owners had sued their project manager for damages. The Court of Appeal had relied on a private appraisal carried out under a clause of the project management contract, which required recourse to an expert chosen by mutual agreement before any litigation. The project manager complained that the judges had relied exclusively on that appraisal.
The Cour de cassation dismissed the appeal (Cass. 3e civ., 8 January 2026, appeal no. 23-22.803, reported decision): “it is otherwise where the appraisal was carried out under the contract concluded by the parties, by an expert chosen by mutual agreement”. The judge then assesses the value and scope of that appraisal’s conclusions in the exercise of its discretion.
What this changes for a property valuation
The single-party report keeps its usefulness, for negotiating, for preparing a claim or written observations to a court expert (dires), and for giving the judge elements that can be cross-checked with other documents. On its own, it is not enough to win a disputed point.
The joint valuation carries more weight, especially when both parties chose the expert together and defined the instruction in writing. The second ruling shows that an expert appointed by mutual agreement under an agreement produces a report on which the judge can rely. A clause of this kind can be inserted in a lease, a shareholders’ agreement, a divorce settlement or a settlement protocol. Articles 1592 and 1843-4 of the French Civil Code organise similar mechanisms for setting a price or the value of company shares.
The quality of the report remains the condition for everything. A joint report is only worth its identified comparables, its explicit methods and its written assumptions, as the Charte requires (Title I, § 4.1.1) and as the EVS 2025 recall for the content of the report (EVS 5). That is what allows the judge, and the opposing party, to check it.
Further reading
The Court expert, joint valuation and litigation support page describes each format, its timescale and its fee. On the same theme: The independence of the expert must be assessed concretely, not presumed and What a valuation report contains. The rulings are available on Légifrance: 15 October 2025 and 8 January 2026.
What next
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