Pre-action expert appraisal in summary proceedings (Art. 145 CPC) before a property or construction dispute

An investor buys an investment building, and six months after signing, cracks run across the façades. A landlord takes back commercial premises wrecked by a tenant who left without leaving an address. A project owner (maître d'ouvrage) finds leaks in an extension delivered last year. In each of these cases, the temptation is to issue proceedings on the merits straight away. This is often a mistake: without technical evidence established on an adversarial basis, the case starts blind. The pre-action expert appraisal in summary proceedings (référé-expertise) based on Article 145 of the French Code of Civil Procedure (CPC) allows a court-appointed expert to be designated before any trial, in order to freeze the defects, quantify the losses and secure a case before taking on the opposing party. This guide details how it works, how to frame the expert's mission, its real cost and its effects on the litigation to come.

The référé-expertise, a tool for building evidence before the dispute

What Article 145 of the Code of Civil Procedure provides

The text is short but decisive. Article 145 of the French Code of Civil Procedure provides:

If there is a legitimate reason to preserve or establish, before any legal proceedings, evidence of facts on which the resolution of a dispute may depend, legally admissible investigative measures may be ordered at the request of any interested party, on application or in summary proceedings.

Three ideas structure this mechanism. First, it operates before any legal proceedings, that is, no action on the merits may already have been started on the same subject matter. Second, it requires a legitimate reason, a notion the courts assess broadly but which remains the central point of control. Third, it opens the door to any admissible investigative measure, the most common of which in property matters is a court-ordered expert appraisal.

The référé-expertise differs from ordinary summary proceedings. The aim is not to have a dispute decided urgently, nor to obtain a provisional award. The claimant seeks neither damages nor the carrying out of works. It asks only that the judge appoint an independent technician to examine a situation and write a report. The condition of urgency, required in ordinary summary proceedings, is moreover not required under Article 145: the Cour de cassation has long accepted that this provision is a free-standing basis, independent of urgency.

Why act before issuing proceedings on the merits

An investor or landlord who discovers a defect has an interest in documenting the technical reality before facing the opponent on the merits. Defects evolve: a crack widens, a leak destroys a floor, a seller acting in bad faith carries out works that erase the traces of a defect. A court-ordered appraisal makes it possible to preserve the evidence before it disappears. It also makes it possible to establish the evidence of a cause, an origin, a costing, all elements that the claimant cannot credibly supply alone before a court.

For a property professional, the référé-expertise performs a strategic function: it allows the strength of the case to be assessed before incurring significant procedural costs. A favourable expert report frequently encourages the opponent to negotiate a settlement. An unfavourable report avoids issuing proceedings at a loss. In both cases, the measure informs the decision whether or not to go to litigation.

Property disputes where the référé-expertise is called for

Hidden defects on purchasing a property

A buyer who discovers after the sale a serious and non-apparent defect has the benefit of the warranty against hidden defects (vices cachés) provided for in Article 1641 of the French Civil Code. Three elements must still be proved: that the defect existed before the sale, that it was hidden, and that it makes the property unfit for its intended use or significantly reduces its value. A court-ordered appraisal for a hidden defect in property is almost always indispensable to establish these points, because the buyer alone cannot demonstrate technically that the defect pre-dated the sale and how serious it is. The regime of the warranty against hidden defects and the buyer's remedies are detailed in our analysis of Articles 1641 to 1649 of the French Civil Code.

The timetable is tight. Article 1648 of the French Civil Code requires action to be brought within two years of discovery of the defect. Issuing a summons for a référé-expertise interrupts the limitation period, which gives a further reason to apply quickly to the judge: it secures the time limit while the expert works.

A concrete example. An investor buys an old flat to let. A few weeks after the purchase, rising damp eats into the ground-floor walls. The seller maintains that the problem appeared after the sale. Without an appraisal, the buyer is helpless: it is the expert appointed in summary proceedings who will determine whether the damp comes from an old structural defect, concealed by cosmetic works carried out before signing.

Construction defects and the ten-year warranty

In construction matters, an expert appraisal is an almost obligatory step. The ten-year liability of builders (responsabilité décennale), based on Article 1792 of the French Civil Code, covers damage that compromises the soundness of the structure or renders it unfit for its intended use for ten years from acceptance. The completion warranty (garantie de parfait achèvement) runs for one year, the two-year functioning warranty (garantie biennale de bon fonctionnement) for two years. Identifying the applicable regime, the nature of the defect and the person responsible requires a technical analysis that only an expert can carry out.

The project owner, often an investor who has had a building constructed or renovated in order to let it, has an interest in having an expert appointed as soon as defects appear. The expert joins all the participants to the proceedings: contractors, the project supervisor (maître d'œuvre), the construction-damage insurer (assureur dommages-ouvrage), subcontractors. This adversarial set-up is essential: a report made without one of the potentially liable parties would be difficult to enforce against that party in the later trial.

Lease disputes and damage to premises

A landlord faced with premises returned in poor condition also has an interest in having the extent of the damage recorded before claiming compensation. The exit inventory is not always enough to cost the reinstatement works precisely, especially where the tenant denies being the cause of the defects or relies on wear and tear. An appraisal makes it possible to distinguish what is normal wear, which is for the landlord's account, from damage attributable to the tenant.

The legitimate reason, the central condition of admissibility

The summary proceedings judge checks that there is a legitimate reason before ordering the measure. This requirement is not a formality. It requires showing that the future proceedings envisaged are neither fanciful nor manifestly doomed to fail, and that the measure sought is useful to their resolution.

In concrete terms, the claimant must set out an identifiable potential dispute: against whom it intends to act, on what legal basis, and how the appraisal will shed light on that future litigation. It need not prove that its claims are well founded, which would contradict the very purpose of the measure. It need only make plausible the existence of a dispute whose resolution depends on the facts to be established.

Two limits should be known. First, the measure must not be ordered if proceedings on the merits are already under way on the same subject matter: the condition "before any legal proceedings" then disappears. Second, the judge refuses requests that are purely exploratory, that is, "fishing expeditions" in which the claimant seeks to obtain information without a genuinely identified dispute. The legitimate reason protects the opponent against unjustified intrusion into its affairs.

Applying to the judge: procedure and framing the mission

Summary proceedings or application: two distinct routes

Article 145 offers two ways of seising the court. The summary proceedings route is adversarial: the opponent is summoned, appears, and may argue against the request before the judge. This is the normal route and by far the most used in property matters, because it guarantees from the outset the adversarial nature of the future operations.

The application route (requête) is exceptional. It allows a measure to be obtained without the opponent being notified, but only where the circumstances require that it not be taken on an adversarial basis, for example to preserve an element of surprise essential to the finding. In matters of construction defects or hidden defects, this route is rarely suitable, because the appraisal is precisely intended to take place in the presence of all the parties. The conditions for using the non-adversarial application under Articles 145 and 493 of the Code of Civil Procedure are examined in our article on business litigation.

The competent court is in principle the judicial court (tribunal judiciaire) of the place where the building is located or of the defendant's domicile. Representation by a lawyer is compulsory before the judicial court for claims exceeding the jurisdictional threshold of the judge for protection disputes (juge des contentieux de la protection), which is the case for most investors' property disputes.

Drafting the expert's mission precisely

The framing of the mission determines the usefulness of the report. A mission that is too vague produces an imprecise report, a mission that is too narrow means going back before the judge to extend it. The claimant has an interest in proposing a detailed outline to the judge, which the judge will adopt or adjust. An effective mission generally asks the expert to:

• visit the site and describe the condition of the building
• record and describe the alleged defects, leaks, cracks or faulty workmanship
• investigate their cause, their origin and the date they appeared
• determine whether they were apparent or detectable at the time of the sale or acceptance
• give an opinion on whether the property is fit or unfit for its intended use
• cost the remedial works and assess ancillary losses (loss of rent, loss of enjoyment)
• provide any information making it possible to identify the persons responsible

In the case of a hidden defect, the question whether the defect pre-dated the sale and was detectable must appear expressly in the mission, because these are the determining elements under Article 1641 of the French Civil Code. In construction, the mission must invite the expert to characterise the defects in light of the statutory warranties and to apportion responsibility among the participants.

Choosing and appointing the expert

The expert is appointed by the judge, not by the parties. The expert is generally chosen from the list of experts attached to the court of appeal, which guarantees competence and independence. The parties may suggest a discipline (structure, damp, thermal, construction economics), but they do not choose the person. The appointed expert must accept the mission and report any conflict of interest.

All persons who may later be pursued must be joined to the proceedings. In construction, this means summoning not only the defaulting contractor but also the project supervisor, the construction-damage insurer and, where applicable, the subcontractors. A participant absent from the operations may later object that the report is not enforceable against it. This work of identifying the parties, often complex, justifies the involvement of a lawyer from the summary proceedings stage.

How the appraisal proceeds

The adversarial principle

A court-ordered appraisal is conducted in compliance with the adversarial principle (contradictoire), guaranteed by the Code of Civil Procedure. The expert convenes all the parties to the site meetings, collects their observations, circulates the documents examined and sends each of them a draft of the conclusions before filing the final report. This respect for the adversarial principle is what gives the report its value: a finding made unilaterally, by an expert instructed by one party alone, does not have the same evidential weight.

The parties put forward their comments by means of dires, written notes addressed to the expert. A well-argued technical dire may alter the expert's analysis or require the expert to give reasons for rejecting it. This is a strategic moment in the litigation where the assistance of a lawyer and, often, of an insurance expert or a technical adviser makes the difference. On the conduct of site visits (accrédits), the drafting of dires and challenging the pre-report, see our analysis of court-ordered property appraisals.

The report and what follows

At the end of the investigations, the expert files a written report. This document describes the defects, identifies their cause, costs the remedial works and gives an opinion, within the limits of the mission, on technical responsibility. It does not decide the legal dispute: apportionment of liability in law is for the trial judge, not the expert.

The report opens up three scenarios. The defect and responsibility are clearly established, and the opponent offers a settlement. The report is nuanced, and the parties negotiate on that basis. The report is unfavourable to the claimant, who then gives up proceedings it would have lost. In every case, the measure has served its purpose: to inform the decision before committing to the merits.

How much a référé-expertise costs

The deposit

The judge who orders the appraisal fixes the amount of an advance, called the deposit (consignation), which the claimant must pay to the court registry to secure the expert's remuneration. Its amount depends on the complexity of the case, the number of parties and the extent of the investigations. It may be revised during the appraisal if the mission proves heavier than expected. Failing payment of the deposit within the time allowed, the expert's appointment lapses, which blocks the whole procedure.

The claimant therefore advances the costs, but this advance is not final: the final burden of costs (dépens), of which the cost of the appraisal forms part, will be decided by the trial judge at the end of the case.

Fees and ancillary costs

The cost of the référé-expertise is made up of several items. The expert's fees, calculated on time spent and the technical nature of the mission, are the main item and are those covered by the deposit. To this are added the lawyer's fees for the appointment procedure and then for following the operations, as well as, frequently, the costs of a technical adviser who assists the party during the appraisal meetings. The overall cost varies widely depending on whether the case concerns an isolated leak or structural defects affecting a whole building.

Who ultimately pays

The principle is that costs are borne by the losing party in the proceedings on the merits. If the investor or landlord succeeds, it can in principle recover the cost of the appraisal from its opponent as costs, together with part of its legal fees under Article 700 of the Code of Civil Procedure. But until the merits are decided, the advance remains at its own expense. This reality must be factored into the decision whether or not to launch the measure.

Effects of the référé-expertise on the litigation to come

Interruption of the limitation period

One of the major effects of the référé-expertise is its impact on time limits for acting. A legal claim, including in summary proceedings, interrupts the limitation period under Article 2241 of the French Civil Code. For a buyer subject to the two-year period of Article 1648 of the French Civil Code in the case of a hidden defect, or for a project owner facing the time limits of the construction warranties, a summons for a référé-expertise secures the position by stopping time from running. This interrupting effect is a decisive reason not to delay applying to the judge once defects are discovered.

The evidential weight of the report

A court-ordered expert report, prepared on an adversarial basis, is a leading item of evidence before the trial judge. Although it does not bind the judge, who retains discretion, in practice it is rarely set aside where it is soundly reasoned. A report produced at the end of operations in which all the parties took part is much harder to challenge than a unilateral assessment.

That is why the quality of the initial framing and the involvement of the parties during the operations weigh heavily on the outcome of the case. A file supported by a favourable appraisal puts the investor or landlord in a strong position, whether to negotiate a settlement or to issue proceedings on the merits.

Conclusion

The référé-expertise is not a preliminary formality: it is the evidential foundation of the future dispute. For an investor or landlord, issuing proceedings on the merits without having had the defects recorded and costed by a court-appointed expert amounts to betting on a badly prepared case. Article 145 of the Code of Civil Procedure offers instead the possibility of freezing the evidence, identifying those responsible, interrupting the limitation period and objectively assessing the strength of one's case before incurring any litigation expense on the merits.

The position taken in this guide is clear: in almost all serious property and construction disputes, the référé-expertise should precede proceedings on the merits, never the other way round. The value of the report depends directly on the care taken in framing the mission and in identifying all the parties to be joined. Before filing an application, have a lawyer check the drafting of the mission and the exhaustive list of persons to be summoned: a participant forgotten today is a liability that cannot be enforced tomorrow.

Frequently asked questions

Is urgency required to obtain a référé-expertise under Article 145 CPC? No. Article 145 of the Code of Civil Procedure is a free-standing basis that does not require urgency to be shown, unlike ordinary summary proceedings. The claimant need only show a legitimate reason to preserve or establish evidence of facts before any legal proceedings. This is an important difference: the measure may be ordered even if there is no particular urgency.

Can a référé-expertise be requested if proceedings are already under way? No. A measure based on Article 145 presupposes acting "before any legal proceedings" on the same subject matter. If an action on the merits has already been started, the appraisal must be sought from the judge seised of the merits, under the provisions on investigative measures during proceedings. The référé-expertise route closes as soon as the dispute is brought on the merits.

What is the time limit for acting in the case of a hidden defect in property? Article 1648 of the French Civil Code requires the action to be brought within two years of discovery of the defect. A summons for a référé-expertise interrupts that period under Article 2241 of the French Civil Code, which secures the position while the expert carries out the investigations. It is therefore advisable to apply to the judge promptly after the defect is discovered.

How much does a référé-expertise cost in property matters? The cost varies with the complexity of the case. The claimant advances a deposit fixed by the judge to pay the expert, to which are added lawyer's fees and, frequently, those of a technical adviser. This advance is not final: the final burden of the appraisal, included in the costs, is decided by the trial judge and in principle falls on the losing party.

Is a court-ordered expert report binding on the trial judge? No, the judge retains discretion and is not bound by the expert's conclusions. In practice, however, an adversarial and soundly reasoned report is rarely set aside. Its strength lies in the fact that all the parties were able to take part in the operations and put forward their observations, which makes it difficult to challenge effectively.

Whom should one summon in a référé-expertise in construction? All the participants who may be pursued on the merits must be joined: contractors, the project supervisor, the construction-damage insurer and the subcontractors concerned. A participant absent from the operations may object that the report is not enforceable against it in the later trial. Identifying the parties exhaustively is one of the most delicate points of the procedure and justifies the involvement of a lawyer.

Can the seller object to the appointment of an expert? The defendant may dispute the existence of a legitimate reason or argue that the request is purely exploratory. The summary proceedings judge assesses these arguments, but the legitimate reason condition is interpreted flexibly where a future dispute is identifiable. In practice, requests that are seriously reasoned and supported by indications of defects most often result in the appointment of an expert.