judicial expertise

Judicial expertise in France: what’s the lawyers’ role?

Among the guiding principles of French civil procedure, respect for the adversarial process, i.e. the right not to be judged without having been heard or called upon to express oneself, is central. Contradiction (or the adversarial nature of the civil trial) fulfils an essential role: it allows the parties to express their opposing points of view, so that the judge can form his/her opinion. In practical terms, this means that each party can contradict the other’s arguments: as they disagree about the facts as they happened, or the situation as it stands.

Accordingly, the onus is on the parties to the civil trial to prove the facts on which they base their claims. However, this essential task is often beyond their capacity. There are many reasons for this: the technical nature of the subject matter, lack of material resources, etc. This is particularly the case in the medical, construction and transport fields, where the parties can generally only speculate, without being sufficiently qualified or objective to reach the truth.

This is where judicial expertise comes in, an investigative measure that can be ordered by the judge when he/she “does not have sufficient information to make a decision” (free translation of Art. 144 of the French Code de procédure civile). When the request for an expert opinion is granted, the judge appoints an expert to advise on one or more technical issues.

This measure may be ordered in the course of a trial (even on appeal). It can also be ordered before the trial has begun, in order to obtain evidence that will later be presented before the court[1] .

As we shall see, lawyer plays a decisive role throughout the process: i.e. before (I), during (II) and after (III) the judicial expertise.

I. The lawyers’ role before the expertise operations are carried out

1.1. Observations specific to expert appraisals ordered in the course of the trial

When they feel the need to do so, judges may call in an expert to shed light on a question of fact relating to an ongoing dispute (Art. 232 of the French Code de procédure civile). As per Art. 143 of the same Code, expert appraisal may either be ordered ex officio or requested by one of the parties to the dispute (claimant or defendant).

When the request is made by a party, its lawyer must ensure that the measure is legally admissible. This is why, with very few exceptions[2], evidence that violates privacy (protected under Art. 9 of the French Code civil) is not admissible.

As the judge is not obliged to grant the requested measure, it must then be shown that it is useful. Art. 146 al. 1 of the Code of Civil Procedure is very clear: “An investigative measure may only be ordered in respect of a fact if the party alleging it does not have sufficient evidence to prove it” (free translation).

Take the example of a person who has suffered personal injury following the collapse of a building. To decide whether to pay compensation, the judge will need to know the cause of the damage. It will therefore be essential to understand what caused the collapse in the first place. Was it caused by work being carried out nearby? By the dilapidated state of the building, or even its ruin? Or a combination of other factors? Similarly, to assess the amount of compensation, he or she will need to measure the nature and severity of the injuries. In either case, it is the legal expert’s report that will help establish the judicial truth.

However, it should be borne in mind that “in no case may an investigative measure be ordered to make up for a party’s failure to provide evidence” (free translation of Art. 146, para. 2 of the French Code de procédure civile). A request to obtain information that the requesting party should itself have provided[3] thus constitutes a failure to provide evidence. The same applies if the evidence can be provided by other, easier means[4] .

Counsel for the opposing party does not remain inactive in the face of the request for expertise.

Depending on his client’s position, he may challenge the appropriateness of the measure before the order is made. He will then rely on the aforementioned provisions (i.e. Art. 143 and 146 para. 2 of the French Code de procédure civile)[5] or argue that the measure requested is pointless.

He may also appeal against the decision ordering the judicial expertise, provided he can show serious and legitimate grounds[6] . Such grounds may be established, for example, where the expert opinion requested is manifestly unnecessary or is merely intended to compensate for the party’s failure to provide evidence. A contrario, if this condition is not met, no opposition to the decision ordering the expert opinion will be possible (as per Art. 150 of the French Code de procédure civile).

Finally, once the expert has been appointed, it will sometimes be possible to ask for him/her to be challenged and revoked. However, this is a rare and exceptional case. The conditions for challenging the expert are identical to those for challenging a judge (Arts. 234 and 341 of the French Code de procédure civile, Art. L. 111-6 of the French Code de l’organisation judiciaire). For example, an expert who has close ties with one of the parties (“friendship or notorious intimacy“), to the point of undermining his impartiality, may be challenged. It is often this breach of the duty of impartiality that is invoked by the challenging party[7] .

1.2. Observations specific to in futurum expertise

As recalled above, a judicial expert opinion may also be ordered prior to any trial. In this case, the investigative measure is called “in futurum“, i.e. its purpose is to establish or preserve, before any trial, “proof of facts on which the resolution of a dispute may depend” (free translation of Art. 145 of the French Code de procédure civile).

As a general rule, the measure requested must be legally admissible. This concept has been clarified by the Cour de cassation in the following terms: “legally admissible measures are investigative measures that are limited in time and purpose and proportionate to the objective pursued” (free translation). The highest court also specified that it is up to the judge to “verify whether the measure ordered was necessary for the exercise of the applicant’s right to evidence and proportionate to the conflicting interests at stake[8] (free translation).

The court hearing an application in futurum does not normally have to consider the nature or admissibility of the future action brought on the merits[9] . It must only assess the admissibility of the measure sought.

The applicant for in futurum expertise must demonstrate its usefulness in terms of the need to establish or preserve evidence in view of a dispute. This means demonstrating the existence of a potential dispute whose resolution could depend on the results of the expert opinion[10] .

As in the case of expert evidence ordered during the trial, the other party’s lawyer may object to the decision granting the requested measure. However, this can only be done after the fact, i.e. after the proceedings have been completed. In this case, once again, serious and legitimate grounds must be provided, such as the futility of the measure requested or the failure of the other party to provide evidence.

N.B. In futurum measures may, as a general rule, be initiated by requête or by assignation en référé. However, if an application is introduced by way of requête, the other party will not be able to put forward its arguments before the measure is ordered. Such an application is indeed subject to proof of specific circumstances justifying the absence of any adversarial debate[11] . This is particularly the case where there is a risk of concealment, alteration or destruction of the evidence, and where surprise is necessary to obtain or preserve it. This typically useful to obtain that a bailiff observes certain wrongful acts or seizes documents. The resolutely adversarial nature of expertise does not therefore seem compatible with this absence of debate.

1.3. Features common to both types of expertise

Whether before or during the trial, lawyers must demonstrate that the expert’s opinion is essential to establish the truth. This is why lawyers produce all the documents in support of the request for a judicial expertise and may even propose an expert approved in the field concerned.

At the end of the day, the decision whether or not to order a judicial expertise rests with the judge, who will have full discretion to rule on the matter.

Once the expert report has been ordered and the expert appointed, without this having been challenged or questioned, the lawyer must ensure that the assignment can be carried out efficiently and under optimum conditions. In practical terms, this means two things. On the one hand, the lawyer must ensure that the advance on the expert’s remuneration is deposited in good time, otherwise the expert’s appointment will lapse[12].Secondly, the lawyer must ensure that the expert is able to carry out his/her mission with full knowledge of the facts – which means that all the relevant documents must be sent to him/her before the operations start.  To this end, a bordereau (official list of documents) is drawn up and sent to the expert. [13]

II. The lawyers’ role during expert appraisal

2.1. Lawyers appease confrontation

During expert appraisals, lawyers often play a facilitating role. This can be a very stressful time, particularly when the trial has already begun. Since the parties have antagonistic or even hostile points of view, their confrontation can be quite anxiety-provoking. The presence of lawyers is therefore invaluable, as they will ensure that the discussions remain relevant and do not overflow the scope of the expert’s mission.

Apart from this purely human function, the lawyer’s assistance fulfils an absolutely essential role in protecting his client’s interests. 

2.2. Lawyers ensure procedural compliance

Lawyers must ensure that the expert assessment is carried out in accordance with the rules of law, in particular the provisions of the Code of civil procedure.

First of all, lawyers must ensure that the adversarial principle is respected. This means that both parties must be informed of the progress of the expert assessment, invited to take part (or be represented) and given the opportunity to make their observations.

An expert report drawn up following an expert appraisal in which one of the parties has not been called risks being annulled[14] , even if the report is subsequently communicated to the parties before debate on the merits [15].

Additionnally, lawyers must ensure that the expert respects the boundaries of his/her mission[16] , as defined in the decision ordering the expertise (Art. 265 of the French Code de procédure civile). Under no circumstances can the expert give an opinion on the classification or attribution of a fault, nor on whether or not a damage must be compensated.

Similarly, it is not possible for experts to determine the intention or motive of the parties, as their investigations can only focus on purely technical and material issues. Accordingly, lawyers will ensure that “the technician appointed [carries out] his task conscientiously, objectively and impartially” (free translation of Art. 237 of the French Code de procédure civile).

2.3. Lawyers prepare and adapt their litigation strategy

The lawyer’s participation in the expert appraisal will enable to draw the expert’s attention to certain important points in the dispute. He/she will ask strategic questions, the answers to which are likely to work in his/her client’s favour.

Given the technical nature of certain areas, lawyers do not always have the necessary level of knowledge to usefully discuss the contentious points of the case. This is why they may recommend that their client be accompanied by a technical adviser, as authorised by Art. 161 of the French Code de procédure civile.

III. The lawyers’ role after the expert assessment has been carried out

3.1. Lawyers draw all the useful conclusions from the expert report

First of all, lawyers ensure that the expert gives his opinion within the time limit set by the judge[17] . Once this time limit has passed, the lawyer can “chase up” the expert, or even refer the matter to the judge responsible for supervising expert appraisal measures.  The applicable law even authorises lawyers to request the replacement of the defaulting expert, for, by not producing his report within the time limit, the latter is failing in one of his duties. It is then up to the judge to decide this question, after hearing the expert’s explanations (Art. 235 para. 2 of the French Code de procédure civile).

In practice, the expert sends the parties a preliminary report setting out his first findings and preliminary conclusions. Each lawyer then submits his comments in one or more “statements”.

In order to respect the adversarial principle (a breach of which may result in the report being null and void), any remarks, observations or complaints must be addressed not only to the expert, but also to the opposing party. It should be borne in mind that it is the party, and not the expert, who is responsible for communicating any exhibits or documents to the other party.

Once the appraisal has been completed, lawyers assess whether it is necessary to request a further expertise (which is often the case in the most complex areas).

3.2. Lawyers adapt their defence when the expert report is unfavourable

The final report will normally be unfavourable to the interests of at least one of the parties. Faced with this situation, the lawyer will consider the most appropriate angle of defence.

In some cases, he/she will call on the additional services of a private expert, i.e. one authorised to give a technical opinion on the subject in dispute, on the initiative and at the expense of one party only. Admittedly, this will be a strictly unilateral expert opinion (i.e. not subject to contradiction). However, case law regularly confirms the evidential value of such a report, provided that it has been submitted to the free discussion of the parties[18] .

Secondly, a request may be made for additional expertise, or even a counter-expertise. Here again, the success of such a request will depend on whether it can be shown to be necessary[19] . For example, the court will order a supplementary expert opinion if it considers that the report in its possession does not provide sufficient information to enable it to make a decision.

A second expert opinion may be ordered if the conclusions of the first expert raise serious doubts (e.g. they are contradictory) and as such require a second look at the facts.

The expert’s findings and conclusions naturally help the judge to assess the facts of the case; however, the judge remains free to make his/her own decision: he/she is not bound by the expert’s opinion (Art. 246 of the French Code de procédure civile).

Finally, lawyers may wish to seek the annulment of the expert report. However, such a serious sanction will only be granted in the event of a clear breach of one or more procedural rules[20] .

N.B. The irregularities that affect the judicial expertise, in particular the failure to respect the adversarial principle, must be invoked in limine litis in order for the report to be annulled. If the party invoking these irregularities does not ask for the report to be annulled, it will in principle remain enforceable against it, which will in turn authorise the judge to base his decision on it. In the event of an irregularity tainting the process, it is therefore advisable to draw all the procedural consequences as soon as possible:

“But whereas, on the one hand, the parties to proceedings in which a judicial expert report has been ordered may not rely on the unenforceability of the expert report on the grounds of irregularities affecting the conduct of the expert report, which are sanctioned in accordance with the provisions of Article 175 of the Code of Civil Procedure, which refer to the rules governing the nullity of procedural documents;

Having noted that the company did not request the annulment of the expert’s report, the clear and precise content of which had been debated in adversarial proceedings before it, the Court of Appeal, having made a sovereign assessment of the value and scope of the evidence submitted for its consideration, was able to take account of the expert’s assessments in setting Mr X.’s compensation[21].


As we have seen, lawyers plays an absolutely decisive role and can exert a positive influence on the course of the judicial expertise before French courts, both upstream and downstream of the process.

We can assist you with expertise measures relating to our litigation areas of expertise, namely:

Private clientsBusinessesInternational
Disputes relating to property transactions (forced sale, cancellation, etc.)
Adjudication (judicial auctions)
Liability claims (tort or contract liability, professional liability, etc.)
Inheritance disputes (actions for annulment, severance, compensatory levy, etc.)
Commercial disputes (breach of contract, commercial lease termination, disputes between associates, etc.)
Private arbitration (defence & representation, arbitral tribunal constitution, etc.)
Competition law (parasitical and unfair competition, etc.)
Company life (debt collection, work relations, commercial liability, etc.)
Seizures & precautionary measures (seizures & summary proceedings…)
Private international arbitration (arbitral tribunal constitution, defence & representation, etc.)
Exequatur & enforcement of foreign judgments (recognition & enforcement of arbitral awards, of foreign judgments, etc.)
International litigation (representation & defence before French courts in complex cross- border disputes, legal opinions, etc.)  

[1] Art. 145 of the French Code de procédure civile

[2] Unless the production of evidence infringing on privacy is essential to the exercise of the right to evidence, and the infringement is proportionate to the aim pursued (Cass. civ. 1ère, 25 February 2016, no. 15-12.403).

[3] Cass. soc, 24 May 1989, no. 86-16.211, Bull.

[4] Cass., Soc., 8 November 1989, no. 88-45.583

[5] Unlawfulness of the measure requested; request for an expert opinion to make up for the failure of the opposing party to provide evidence

[6] Art. 272 para. 1 of the Code of Civil Procedure

[7] See Bordeaux Court of Appeal, 1st Civil Division, 2 June 2022, RG no. 21/06813.

[8] Cass. civ. 2ème, 25 March 2021, no. 20-14.309

[9] See Cass. civ. 2ème, 29 September 2011, no. 10-24.684

[10] See Cass. civ. 2ème, 16 November 2017, no. 16-24.368.

[11] Cass. civ. 2ème, 3 March 2022, no. 20-22.349

[12] Art. 269-271 of the French Code de procédure civile

[13] CNB, Recommendations on good practice between lawyers and experts

[14] Cass. civ. 2ème, 15 April 2010, no. 09-10.239

[15] Cass. civ. 1ère, 7 March 2000, no. 97-20.017

[16] Which can, however, be extended through the extension of mission procedure.

[17] Art. 265 of the French Code de procédure civile

[18] See in particular Cass. civ. 1ère, 24 September 2002, no. 01-10.739

[19] Cass. civ. 2, 26 June 2008, no. 07-13.875

[20] Art. 175 of the French Code de procédure civile

[21] Cass. Ch. mix., 28 Sept. 2012, no. 11-11.381

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