Mandatory Diagnostics for the Sale of Real Estate 2026

In 2026, selling a flat or a house without presenting the right set of diagnostic reports exposes the seller to a real risk: annulment of the sale, a reduction in price or an order to pay damages. These obligations have multiplied and hardened, notably as a result of the Climate and Resilience Act, which makes the energy audit unavoidable for the most energy-intensive homes. An owner who had diagnostic reports prepared in 2019 often discovers, at the time of signing, that some of them are no longer valid. This guide details the list of mandatory diagnostic reports for a sale of real estate in 2026, their period of validity, who pays for them, and what happens if one is missing or wrong.

The technical diagnostic file: the foundation of every sale

The sale of real estate requires the seller to hand the buyer a set of documents grouped together under the name technical diagnostic file (dossier de diagnostic technique, DDT). Article L271-4 of the French Construction and Housing Code provides that this file is annexed to the promise to sell or, failing a promise, to the authentic deed of sale. The documents to be assembled for signature of the preliminary agreement, diagnostic reports included, are listed in our article on the documents for a preliminary sale agreement (compromis de vente).

The principle is simple: the buyer must be able to buy with full knowledge of the facts. Diagnostic reports are not administrative formalities, they are items of information on the real condition of the property (presence of asbestos, energy performance, natural risks, compliance of installations). They condition the buyer's consent and, in the event of a serious defect, may call the sale into question.

The exact content of the file depends on three factors: the year of construction of the building, its geographical location and the nature of the dwelling (detached house, co-ownership lot, presence of a gas or electrical installation more than fifteen years old). A studio built in 2018 in the middle of Paris and a Breton longhouse from 1930 do not require the same diagnostic reports.

The list of mandatory diagnostic reports in 2026

Here, report by report, is what you need to know before putting a property on the market.

The energy performance diagnostic (DPE)

The energy performance diagnostic (diagnostic de performance énergétique, DPE) is now the central report. It rates the dwelling from A (very efficient) to G (thermal sieve) according to its energy consumption and its greenhouse gas emissions. Since the reform that came into force on 1 July 2021, the DPE has become enforceable: the buyer may engage the seller's liability on the basis of the information it contains, which was not the case previously when it had a purely informative value.

The energy rating must appear in the sale advertisement itself. Article L126-33 of the French Construction and Housing Code requires that:

In the event of the sale or letting of real estate, the rating of the property with regard to its energy performance and, for residential property and for information purposes, an indication of the amount of theoretical expenditure for all the uses listed in the energy performance diagnostic are stated in advertisements relating to the sale or letting.

This display obligation applies to all advertisements, whether posted in an agency window (Article R126-22) or published online on a website or an application (Article R126-23). In practical terms, an estate agent's advertisement or a message published on a platform must state the energy label and the estimate of annual expenditure. Failure to include this information is a breach that may be penalised.

One technical point deserves attention in 2026: the DPE calculation method for small surface areas (dwellings of 40 square metres or less) was corrected with effect from 1 July 2024, which allowed many small dwellings to move out of bands F and G. An owner of a studio rated F before that date has every interest in having the DPE redone before selling.

The asbestos diagnostic

The asbestos diagnostic (état d'amiante) applies to all properties for which the building permit was issued before 1 July 1997, the date on which asbestos was banned in construction. It looks for the presence of materials and products containing asbestos (sprayed coatings, insulation lagging, false ceilings, floor tiles, ducts).

Beware of a frequent subtlety: an asbestos diagnostic carried out before 2013 no longer meets current regulatory requirements. Many sellers present an old document that in fact has to be redone. Take an owner reselling in 2026 a flat bought in 2010 with an asbestos report from that time: this document will have to be updated. The survey required of the client (maître d'ouvrage) before starting renovation works is dealt with separately in our article on asbestos surveys before works.

The lead exposure risk report (CREP)

The lead exposure risk report (constat de risque d'exposition au plomb, CREP), or lead diagnostic, is mandatory for dwellings built before 1 January 1949, a period when lead-based paints were commonly used. It measures the lead concentration of coatings and flags, where applicable, situations of deterioration likely to present a health risk, in particular for young children.

The termite diagnostic

The termite diagnostic is mandatory only in areas delimited by a prefectoral order, that is, municipalities declared contaminated or exposed to the risk. A seller in the south-west or around the Mediterranean, regions where infestation is frequent, will very often be concerned, whereas an owner located outside such an area will have no obligation. It is therefore necessary to check with the town hall or the prefecture whether the municipality is the subject of such an order.

The gas and electricity diagnostics

Two separate diagnostics concern the safety of internal installations:

• the report on the internal gas installation is required where the installation is more than fifteen years old;
• the report on the internal electrical installation is required on the same conditions, for an installation more than fifteen years old.

These diagnostics flag dangerous anomalies (no earthing, obsolete electrical panel, potential leak on a gas pipe). They do not oblige the seller to carry out the works, but they inform the buyer of the level of safety of the dwelling. A house from the 1980s that has never been renovated will almost always show electrical anomalies to be reported.

The risk statement (formerly ERP)

The risk statement (état des risques), formerly called the statement of risks and pollution (état des risques et pollutions, ERP), informs the buyer of natural risks (flooding, ground movement, seismicity), mining and technological risks, as well as the radon risk and exposure to coastal erosion. This document relies on the risk prevention plans approved by the prefect and must be drawn up from an official form and the information available on the dedicated portal.

For some years now, this document must be provided from the first viewing of the property, and no longer only at signing. A buyer who discovers late that the dwelling is in a flood zone may legitimately turn against the seller.

The non-mains drainage diagnostic

Where the dwelling is not connected to the public wastewater collection network (a frequent case in rural areas, with a septic tank or micro-treatment plant), the seller must provide an inspection document for the non-mains drainage installation (assainissement non collectif), drawn up by the public non-mains drainage service (SPANC). This inspection checks the compliance of the installation. If it is non-compliant, the buyer may be required to carry out the compliance works within a defined period after the purchase.

Carrez law measurement

For any co-ownership lot (a flat, but also a commercial unit or a cellar attached to a main lot), the seller must state the private floor area according to the Carrez law (loi Carrez). This measurement excludes areas with a ceiling height of less than 1.80 metres, as well as cellars, garages and parking spaces.

The stakes are financial: if the actual area is more than one twentieth (5%) lower than that stated in the deed, the buyer may request a proportionate reduction in the price. A detached house not subject to the co-ownership regime is not covered by the Carrez law, but falls, where relevant, under the Boutin law for the habitable surface area in the event of letting.

The noise diagnostic

More recent, the statement of aircraft noise nuisance concerns properties located in a noise exposure zone defined by a noise exposure plan (plan d'exposition au bruit, PEB) around airports. It informs the buyer of the existence of noise nuisance linked to air traffic. A flat close to a major airport platform will typically be concerned.

The energy audit: the major development

The energy audit is not the same as the DPE. Where the DPE establishes a rating, the energy audit proposes a costed programme of works to improve the performance of the dwelling and reach a better rating. It stems from the Climate and Resilience Act of 22 August 2021.

The implementation timetable is progressive and concerns the sale of detached houses and buildings in single ownership (a single owner for the whole building):

• since 1 April 2023 for dwellings rated F or G;
• since 1 January 2025 for dwellings rated E;
• from 1 January 2034 for dwellings rated D.

In 2026, a seller of a house rated E, F or G must therefore have an energy audit carried out in addition to the DPE. This audit is provided from the first viewing and annexed to the promise as well as to the deed. It should be noted that dwellings under the co-ownership regime are not subject to this audit obligation on sale, which specifically targets houses and buildings held by a single owner.

This development forms part of the broader movement of progressive prohibition on letting thermal sieves. Letting of dwellings rated G has been prohibited since 1 January 2025, that of dwellings rated F will be from 2028, and that of dwellings rated E from 2034. An investor who buys a poorly rated property today must factor these deadlines into the calculation. For the acquisition of a whole building, see our analysis of the collective DPE and the energy audit as regards the viability of an income-producing building.

The period of validity of diagnostic reports

The most common mistake is to present expired diagnostic reports. Each report has its own period of validity, and the expiry of one of them may block a signing. The list below summarises the applicable periods:

• DPE: 10 years (with a major reservation, see below);
• energy audit: 5 years;
• asbestos: unlimited where there is no asbestos (subject to a document complying with current regulations);
• lead (CREP): unlimited if the report is negative, 1 year if it is positive;
• termites: 6 months;
• gas: 3 years;
• electricity: 3 years;
• risk statement: 6 months;
• non-mains drainage: 3 years;
• Carrez law measurement: no statutory period, but to be redone if the areas are modified.

As regards the DPE, a transitional rule has reduced the validity of older reports. DPEs carried out between 1 January 2013 and 31 December 2017 ceased to be valid at the end of 2022, and those drawn up between 1 January 2018 and 30 June 2021 expired at the end of 2024. In 2026, only DPEs drawn up under the new method, that is, since 1 July 2021, remain valid. A seller who digs out a 2019 DPE believing it valid for ten years is mistaken: it will have to be redone.

Who carries out the diagnostic reports and who pays for them

Diagnostic reports must be drawn up by a diagnostician certified by an accredited body and holding professional liability insurance. Using a non-certified professional makes the report unenforceable and engages the seller's liability.

The cost of diagnostic reports is, unless otherwise agreed, borne by the seller. It varies significantly according to the surface area of the property, the number of reports required and the location. It is better to request several quotes and to have all the reports carried out by the same operator in a single visit, which reduces the cost and limits the risk of inconsistency.

A practical tip: it is prudent to group the preparation of the diagnostic reports at the time the property is put on the market, and not earlier, so that the short-validity reports (termites, risk statement) are not out of date on the day of signing. If the sale drags on, some documents will have to be updated.

The consequences of a missing or erroneous diagnostic report

The absence of a diagnostic report does not automatically render the sale void, but it deprives the seller of the protection offered by the clause excluding the guarantee against latent defects (garantie des vices cachés). In plain terms, where the seller does not provide a mandatory report, or provides an erroneous one, the seller can no longer shelter behind the non-warranty clause usually inserted in deeds. The buyer may then bring an action for latent defects.

The possible consequences are graduated:

• a request for a reduction in the sale price proportionate to the defect found;
• a claim for damages for the cost of remedial works;
• in the most serious cases, annulment of the sale where the defect makes the property unfit for its purpose or the buyer would not have bought had the defect been known.

Case law has long accepted that a buyer misled by an erroneous diagnostic report may turn against the seller as well as against the diagnostician, whose professional liability is engaged. For the DPE, now enforceable, a manifestly false energy rating may thus give rise to compensation where the buyer shows loss (for example, energy bills unrelated to the label announced).

Finally, failure to display the energy rating in the advertisement, in breach of Articles L126-33, R126-22 and R126-23 of the French Construction and Housing Code, exposes the seller or the intermediary to administrative penalties. This obligation is therefore not merely symbolic.

Conclusion

The overall logic of mandatory diagnostic reports in 2026 is clear: less tolerance for expired or approximate documents, and a growing weight given to energy performance. The DPE has become enforceable, the energy audit now applies to dwellings rated E, F and G that are detached houses or in single ownership, and thermal sieves see both their resale value and their letting potential decline as the letting bans come into force.

The position to adopt is as follows: an informed seller does not treat diagnostic reports as a last-minute formality, but as an element of the legal security of the sale. Before putting a property on the market, have the whole technical diagnostic file drawn up by a certified diagnostician, check the date of each document against its period of validity, and anticipate the energy audit if the DPE rates the property E, F or G. If in doubt about the enforceability of an old report or the consequences of an anomaly revealed, legal advice before signing always costs less than litigation after the sale.

Frequently asked questions

Which diagnostic reports are mandatory to sell a house in 2026?

For a detached house, the list of sale diagnostic reports includes, depending on the age and situation of the property: the DPE, the asbestos diagnostic (permit before 1 July 1997), lead (construction before 1949), termites (area subject to a prefectoral order), the reports on gas and electrical installations more than fifteen years old, the risk statement, non-mains drainage if the property is not connected, and the noise diagnostic in an airport zone. The energy audit is added if the house is rated E, F or G. The Carrez law does not apply to a house outside a co-ownership.

Is a 2019 DPE still valid for a sale in 2026?

No. Because of the transitional rules, DPEs carried out between 1 January 2018 and 30 June 2021 ceased to be valid on 31 December 2024. In 2026, only DPEs drawn up since 1 July 2021, under the current method, remain valid for a period of ten years. A 2019 DPE must therefore be redone before the property is put on the market.

Is the energy audit mandatory for all dwellings in 2026?

No, it applies to detached houses and buildings in single ownership rated E, F or G in the DPE. The obligation has applied since 1 April 2023 for bands F and G, since 1 January 2025 for band E, and will extend to band D on 1 January 2034. Lots in co-ownership are not subject to this audit on sale.

Who pays for property diagnostic reports on a sale?

Unless the parties agree otherwise, diagnostic reports are borne by the seller. They must be carried out by a certified and insured diagnostician, failing which they are unenforceable. The cost depends on the surface area, the number of reports required and the location of the property.

What does the seller risk if a mandatory diagnostic report is omitted?

Omission of a report deprives the seller of the clause excluding the guarantee against latent defects. The buyer may then request a price reduction, damages, or even annulment of the sale if the defect makes the property unfit for its purpose. The diagnostician at fault may also have professional liability engaged.

Must the energy rating be displayed in the sale advertisement?

Yes. Articles L126-33, R126-22 and R126-23 of the French Construction and Housing Code require the energy rating of the property and, for information purposes, an estimate of annual energy expenditure to be stated in any sale advertisement, whether displayed in an agency or published online. Failure to include this exposes the seller to administrative penalties.

How long do diagnostic reports remain valid?

The periods vary: 10 years for the DPE, 5 years for the energy audit, 3 years for the gas, electricity and non-mains drainage reports, 6 months for termites and the risk statement, 1 year for a positive lead report. The asbestos diagnostic is unlimited where there is no asbestos and the document is compliant, and the lead report is unlimited if negative. It is prudent to have the short-validity reports carried out just before the property is put on the market.