Judicial experts
Legal background
Consequences and effects


Under French law, a party wanting to preserve or establish evidence of facts on which the solution of a dispute might depend can ask the judge before the trial commences to appoint a judicial expert to draft a report regarding the matter (Article 145 of the Code of Civil Procedure).

On receipt of the expert report (which often takes months or years of judicial investigation), a party can use its findings to seek compensation from the other party. In this instance, the other party may want to seek – by way of exception – nullification of the report.

Article 246 of the Code of Civil Procedure states that judges are not bound by a judicial expert's findings. In practice, however, judges have confirmed expert findings in more than 90% of cases, which shows the importance of such pre-trial proceedings in France.

While nullification of an expert report may be sought by a dissatisfied party, applicants should be aware that the conditions on which it can be ordered are strictly defined by case law. In addition, although the effects of nullification can be powerful, they can also be disappointing.

Judicial experts

Articles 232 and following of the Code of Civil Procedure define the rights and obligations of judicial experts. First, they must perform the assignment conscientiously, objectively and impartially in accordance with the adversarial principle and must not express any legal opinion.

Second, the expert must personally carry out the assignment. Although it is possible to appoint a sapiteur (ie, an expert specialised in a different field), the court-appointed expert must remain in control and is responsible for the assignment and the final report.

Third, in the event of any difficulty while performing the assignment, either party or the expert can refer to the responsible judge. A request may be filed with the judge for a time extension or amendment of the assignment.

Finally, given the duty of impartiality imposed on them, judicial experts can be removed on the same grounds as judges.

Legal background

The nullification of an expert report is subject to the provisions of the Code of Civil Procedure governing the nullification of proceedings (Article 178-175). The nullity request will be raised by way of exception, but will in any case be invoked in limine litis (ie, before the filing of any other legal argument).

Thus, the Court of Cassation has ruled that if a request for the nullification of an expert report is not made until the trial has commenced, such action is inadmissible.(1)

Therefore, litigants should invoke nullity on the merits before any defence to avoid any risk of inadmissibility.


The nullification of an expert report requires a ruling expressly providing for nullification, evidence of harm caused by the expert's non-compliance and a lack of regularisation.

Conversely, substantive nullification is not subject to evidence of harm or to the existence of a ruling specifically providing for such an outcome.

In general, an expert report may be nullified only where there is consistent evidence of the expert's non-compliance with the Code of Civil Procedure.

Thus, if the assignment has been undertaken by a third party (including a sapiteur) and not by the expert, the report can be subject to nullification. The plaintiff requesting nullification must precisely demonstrate any instances of non-compliance – for example, by citing passages of the report where the expert consistently refers to the sapiteur report with no further analysis or without drawing any conclusions.(2) In this regard, case law considers that a sapiteur's opinion should be treated as any other information collected by the expert.(3) As such, it should be subject to critical analysis and the parties' submissions.

Similarly, infringement of the adversarial principle (which underpins the French rules governing procedures) – depending on its seriousness – may be considered substantial non-compliance and lead to nullification of the expert report without the need to provide evidence of harm.

This is particularly the case when a party was not informed of part of the ongoing investigation and had no opportunity to address the expert's report,(4) or when the expert did not allow the parties to dispute a document on which the expert had based his or her assessment before filing the report.(5)

Conversely, if the expert report includes legal opinions – which are prohibited – the report will not necessarily be void. Instead, case law gives judges discretion to decide.

Nullity actions cannot be taken lightly; it is not enough to invoke vague arguments or arguments for which there is little evidence. The court will conduct a thorough factual analysis and declare the expert's report void only in the presence of indisputable elements.

Consequences and effects

The consequences of nullification can be serious and will be determined by the court. The expert may be denied compensation, he or she may incur liability and the parties may be deprived of the report's conclusions – sometimes after years of investigation.

Although it is rare for judgments to declare expert reports void, applicants must be informed of these consequences before undertaking nullity proceedings.

If the applicant obtains nullification of an expert report, the effects can either be powerful or disappointing.

Under Article 176 of the Code of Civil Procedure, nullification of an investigation does not necessarily entail nullification of the entire report. If the full report is nullified, the opponent can still invoke the report as its existence is not annihilated by the declaration of nullity.

The judge may, depending on the facts and requests submitted by the parties, appoint a different expert to undertake a new investigation. However, this is not always possible – especially when actions have been taken after the filing of the report to limit damage resulting from wrongful behaviour.

Another possibility is that the judge may make a decision without considering the nullified report. This is usually the aim of the applicant requesting nullification as it will deprive its opponent of its main advantage.

The report may also be declared void but still be considered by the court, which is the least favourable option for the applicant. Although the nullified report will become only an 'element of fact', this interim solution – recognised by established case law – deprives nullification of its expected radical effect.


Just as case law requires an expert report to be corroborated by further evidence, a nullified report cannot be the only basis on which a judgment is rendered. The Court of Cassation has quashed judgments that are based only on a nullified expert report.(6)

However, this is a serious threat to the applicant seeking nullification even if the report does not, in theory, have the same legal effect once declared void.

For further information on this topic please contact Nicolas Contis or Julie Gayrard at Kalliopé by telephone (+33 1 44 70 64 70) or email ([email protected] or [email protected]). The Kalliopé website can be accessed at


(1) Cass Civ 3rd, February 11 2004, 02-19025.

(2) Cass Civ 2nd, January 11 1995, 93-14697.

(3) CA Aix-en-Provence, September 17 2008, Docket 07/08,715.

(4) Cass Civ 2nd, November 24 1999, 97-10572.

(5) Cass Civ 1st, February 1 2012, 10-18853.

(6) Cass Civ 2nd, November 9 1976, D1977, IR 77.