The technical diagnostics file (DDT, or Dossier de Diagnostics Techniques) is a set of mandatory inspections that the seller must provide to the buyer during any property transaction in France. In 2026, this file can include up to 10 diagnostics for a pre-war Parisian apartment, each with its own validity period. Failure to comply with these diagnostics exposes the seller to penalties and may allow the buyer to cancel the sale or obtain a price reduction.
Introduction
For a buyer in Paris, property diagnostics are not mere administrative formalities. They reveal the actual condition of the property and directly influence its value. An EPC rated F can reduce an apartment’s value by 10 to 20%. A positive asbestos diagnostic determines what renovation work can be done. An unfavourable electrical report signals future investment needs. Understanding each diagnostic, its scope and its validity period is essential for negotiating and buying with full knowledge. This guide covers all mandatory diagnostics in 2026 for a sale in Paris.
Contents
- The EPC: Energy Performance Certificate
- The asbestos diagnostic
- The lead risk assessment (CREP)
- The electrical diagnostic
- The gas diagnostic
- The termite inspection
- The environmental risk assessment (ERP)
- The dry rot diagnostic
- The noise diagnostic
- The loi Carrez measurement
The EPC: Energy Performance Certificate
The EPC (known in France as the DPE, Diagnostic de Performance Énergétique) has become the most scrutinised diagnostic in the Parisian property market. It evaluates a home’s energy consumption and greenhouse gas emissions, assigning a rating from A (very efficient) to G (very energy-intensive).
The “3CL” calculation method (Calcul de la Consommation Conventionnelle des Logements), reformed in 2021, is based on the building’s physical characteristics rather than actual energy bills. This method has penalised a significant portion of Paris’s Haussmannian housing stock, built before any thermal regulation existed.
In 2026, the breakdown of the Parisian housing stock is approximately as follows: 5% of homes rated A-B, 15% rated C, 30% rated D, 30% rated E, 15% rated F and 5% rated G. G-rated homes have been banned from the rental market since 1 January 2025. F-rated homes will follow from 2028.
The EPC is valid for 10 years. It costs between 150 and 250 euros for a standard Parisian apartment. It has been legally binding since 2021, meaning the buyer can hold the seller liable in the event of a significant error.
The asbestos diagnostic
The asbestos diagnostic is mandatory for any building whose construction permit was issued before 1 July 1997, the date asbestos was banned in France. In Paris, this covers virtually the entire Haussmannian housing stock and a large proportion of post-war buildings.
The certified diagnostician looks for asbestos-containing materials in the construction: sprayed coatings, pipe insulation, floor tiles, joints, adhesives and plasters. If asbestos is detected, the report classifies the condition of the materials on a three-level scale. Level 1 requires only periodic monitoring. Level 2 requires a further assessment. Level 3 demands containment or removal work within 36 months.
The asbestos diagnostic is valid indefinitely if no asbestos is detected. If present, periodic monitoring (every 3 years) is required. The cost ranges from 80 to 150 euros for an apartment.
The lead risk assessment (CREP)
The CREP (Constat de Risque d’Exposition au Plomb) is mandatory for any property built before 1 January 1949. In Paris, the Haussmannian stock (1850-1914) and inter-war buildings are systematically affected. Old paints frequently contain lead, a toxic substance if ingested or inhaled as dust.
The diagnostician measures the lead concentration of coatings (paints, plasters) using an X-ray fluorescence device. If the concentration exceeds the regulatory threshold of 1 mg/cm2, the report identifies the affected coatings and their state of deterioration.
The CREP is valid indefinitely if no lead is detected above the threshold. If present, the validity is 1 year for a sale and 6 years for a rental. The cost is around 100 to 200 euros depending on the surface area and number of rooms.
For a buyer in the 6th or the 7th arrondissement, where the vast majority of the housing stock predates 1949, a positive CREP is common and should not necessarily discourage a purchase. Covering works (applying glass fibre, repainting) are generally sufficient to neutralise the risk.
The electrical diagnostic
The electrical diagnostic is mandatory for any installation older than 15 years. It assesses the installation’s compliance with safety standards: presence of a main circuit breaker, earth connection, residual current protection, adequate cable sizes.
The report identifies defects but does not constitute a compliance upgrade. The most common defects in older Parisian apartments are the absence of earthing, inadequate cable sizes, and the lack of residual current protection in bathrooms.
The validity period is 3 years for a sale and 6 years for a rental. The cost ranges from 100 to 150 euros. For a buyer, an unfavourable electrical diagnostic signals an upgrade investment of around 80 to 150 euros/m², or 5,000 to 10,000 euros for a 65 m² apartment.
The gas diagnostic
The gas diagnostic is mandatory for any gas installation older than 15 years. It checks the condition of fixed heating and hot water appliances, fixed supply pipes, room ventilation and combustion.
In Paris, many older apartments still have gas installations for individual heating or cooking. The most common defects are inadequate ventilation in rooms with gas appliances and ageing supply pipes.
The validity period is 3 years for a sale and 6 years for a rental. The cost is 100 to 150 euros. In the event of a serious and immediate danger (DGI), the diagnostician shuts off the gas supply and the distributor is notified.
The termite inspection
The termite inspection is mandatory in areas designated by prefectoral decree. Paris has been classified as a termite risk zone since the prefectoral decree of 1 September 2006. The entire capital is therefore affected.
The diagnostician inspects accessible wooden elements (floors, skirting boards, frames, roof structures) and walls for signs of termite activity. The diagnostic covers the private areas of the unit being sold.
The validity period is 6 months. This short deadline justifies carrying out the inspection as close as possible to the signing of the preliminary sales agreement. The cost is 100 to 200 euros. For a comprehensive overview of all wood parasites, see our guide on the parasitic condition report.
The environmental risk assessment (ERP)
The ERP (État des Risques et Pollutions) informs the buyer about natural risks (flooding, ground movement), mining, technological, seismic, coastal erosion and soil pollution risks to which the property is exposed. This document is based on prefectoral decrees and risk prevention plans.
In Paris, the main identified risks are the Seine flood risk (PPRI zones in the 1st, 4th, 5th, 6th, 7th, 12th, 13th, 15th and 16th arrondissement), the ground movement risk linked to former underground quarries, and the seismic risk (zone 1, very low).
The validity period is 6 months. The seller can prepare this document themselves using information available on the Géorisques website of the Ministry for Ecological Transition. Most diagnosticians include it in their package.
The dry rot diagnostic
The dry rot (merule) diagnostic is not yet strictly mandatory for all sales, but must be carried out in areas identified by prefectoral decree as risk zones. Paris is not subject to a specific decree, but certain Île-de-France municipalities are affected.
In practice, the diagnostician may note the presence of dry rot during a moisture or termite inspection. Dry rot is a wood-destroying fungus that develops in damp, poorly ventilated timber. Its presence signals a structural moisture problem requiring extensive work.
For a buyer, vigilance is needed in older buildings with lower floors (ground floor, first floor) and waterproofing issues.
The noise diagnostic
The noise diagnostic, officially the “airborne noise nuisance report”, has been mandatory since 1 June 2020 for any property located in an airport noise exposure zone, defined by a Noise Exposure Plan (PEB). In Paris proper, this diagnostic is not required because the capital is not covered by a PEB. However, it applies to Île-de-France municipalities near Roissy-CDG, Orly and Le Bourget airports.
This diagnostic is an informational document. It has no legal validity period but must reflect the situation at the time of the sale. It is prepared from public PEB data and does not require a visit by the diagnostician.
The loi Carrez measurement
The loi Carrez measurement is mandatory for any sale of a co-ownership unit. It measures the private surface area of the unit, excluding surfaces where the ceiling height is below 1.80 m, walls, partitions, steps and stairwells, door and window recesses, and units smaller than 8 m2.
Measurement accuracy is essential: if the actual surface is more than 5% smaller than the surface stated in the deed of sale, the buyer has one year after signing to request a proportional price reduction. To understand the difference with the habitable surface area, see our dedicated article.
The loi Carrez measurement is valid indefinitely, unless works modify the surface (removing a partition, creating a mezzanine). The cost is 70 to 150 euros depending on the property size.
FAQ
How much does a complete technical diagnostics file cost for an apartment in Paris?
A complete DDT for a Parisian apartment costs between 300 and 700 euros depending on the surface area and the number of diagnostics required. The EPC alone costs approximately 150 to 250 euros. It is advisable to use a certified diagnostician who performs all the diagnostics in a single visit.
Who pays for property diagnostics, the seller or the buyer?
Property diagnostics are the seller’s responsibility. The seller must provide them to the buyer no later than the signing of the preliminary sales agreement. If a diagnostic is missing or invalid, the seller cannot invoke the exclusion clause for hidden defects.
Can an expired property diagnostic block a sale?
Yes. The notaire requires valid diagnostics to draft the deed of sale. An expired EPC (valid for 10 years), an expired electrical diagnostic (valid for 3 years) or a risk assessment older than 6 months must be renewed before signing, or the sale may be postponed.
Is the EPC mandatory for homes rated F or G in 2026?
Yes, the EPC is mandatory for all homes regardless of their energy rating. Moreover, since 1 January 2025, G-rated homes have been banned from the rental market. F-rated homes will be banned from 2028. Sale remains possible, but the EPC directly influences the price.
Looking to buy in Paris with confidence? Our property hunters analyse every technical diagnostic and its impact on the property’s value before recommending a purchase. Contact our team for expert guidance.
Frequently asked questions
How much does a complete technical diagnostics file cost for an apartment in Paris?
A complete DDT (Dossier de Diagnostics Techniques) for a Parisian apartment costs between 300 and 700 euros depending on the surface area and the number of diagnostics required. The EPC alone costs approximately 150 to 250 euros. It is advisable to use a certified diagnostician who performs all the diagnostics in a single visit.
Who pays for property diagnostics, the seller or the buyer?
Property diagnostics are the seller's responsibility. The seller must provide them to the buyer no later than the signing of the preliminary sales agreement (compromis de vente). If a diagnostic is missing or invalid, the seller cannot invoke the exclusion clause for hidden defects.
Can an expired property diagnostic block a sale?
Yes. The notaire requires valid diagnostics to draft the deed of sale. An expired EPC (valid for 10 years), an expired electrical diagnostic (valid for 3 years) or a risk assessment older than 6 months must be renewed before signing, or the sale may be postponed.
Is the EPC mandatory for homes rated F or G in 2026?
Yes, the EPC is mandatory for all homes regardless of their energy rating. Moreover, since 1 January 2025, G-rated homes have been banned from the rental market. F-rated homes will be banned from 2028. Sale remains possible, but the EPC directly influences the price.
