Mandatory Real Estate Diagnostic: Complete List 2026

Mandatory Real Estate Diagnostic: Complete List 2026The sale of real estate in France requires the seller to submit aTechnical Diagnostic File (DDT)

to the purchaser, annexed to the promise of sale or to the authentic deed. In 2026, regulations will be strengthened, particularly on the energy side with the gradual ban on the rental of thermal strainers. Mastering the exhaustive list of mandatory diagnostics is therefore essential to legally secure the transaction and avoid post-sale disputes. This article provides a complete update on the diagnostics required in 2026 depending on the nature of the property, its location and its year of construction.

The legal framework of the Technical Diagnostic FileThe DDT is governed by articlesL.271-4 to L.271-6 of the Construction and Housing Code (CCH) ⬥⬥⬥. Its absence engages the seller's liability and may result in the cancellation of the sale, a reduction in the price, or even action under warranty for hidden defects. Each diagnosis must be carried out by aCOFRACcertified diagnostician, in accordance with decree no. 2006-1114. The validity period varies depending on the type of diagnosis, and an expired document cannot be used against the purchaser.

certified diagnostician, in accordance with decree no. 2006-1114. The validity period varies depending on the type of diagnosis, and an expired document cannot be used against the purchaser.

List of 10 mandatory diagnostics in 20261. Energy Performance Diagnosis (DPE)

— Mandatory for all housing, valid for 10 years. Since 2025, G-rated housing has been prohibited for rental; F will be in 2028.2. Asbestos Diagnosis

— Mandatory for properties for which the building permit is prior to July 1, 1997. Unlimited duration if absence detected.3. Lead Exposure Risk Report (CREP)

— For housing built before January 1, 1949. Valid for 1 year if positive, unlimited if negative.4. Condition relating to the presence of termites

4. Condition relating to the presence of termites— Mandatory in areas defined by prefectural decree. Validity 6 months.

5. Condition of the interior gas installation— For installations over 15 years old. Valid for 3 years.

6. Condition of the interior electrical installation— For installations over 15 years old. Valid for 3 years.

7. State of Risks and Pollution (ERP)— Mandatory in areas affected by a PPR (natural, mining, technological), seismicity, radon. Validity 6 months.

8. Non-collective sanitation diagnosis8. Non-collective sanitation diagnosis

— For housing not connected to sewerage. Valid for 3 years.9. Carrez Law measurement

— For any co-owned lot (excluding cellars, garages, terraces). Unlimited duration except for modifying works.

10. Energy audit— Mandatory since April 1, 2023 for the sale of housing classified F or G, extended to classes E in 2025 and D in 2034.Sanctions and responsibilities in the event of breachThe absence of a mandatory diagnosis deprives the seller of the clause exemption from warranty for hidden defects (⬥⬥⬥ article 1641 of the Civil Code ⬥⬥⬥). An erroneous DPE can now engage the liability of the diagnostician AND the seller, since its enforceable nature established by theClimate and Resilience law of August 22, 2021 ⬥⬥⬥. Criminal sanctions can reach a fine of €37,500 for false declaration concerning asbestos or lead.