Guide
Reading a French property diagnostic report in English
When you buy a property in France, the seller hands you a thick folder of technical reports called the Dossier de Diagnostic Technique, almost always abbreviated to DDT. The reports inside are written in French, use regulatory terminology, and arrive shortly before you're expected to sign the compromis de vente. If you can't read French, the experience can feel overwhelming. This guide explains what each document covers, what you should look for, and what a problem finding actually means in practice.
Diagnostic reports inform your purchase decision but don't substitute for legal advice. Have a French notaire (or a bilingual property lawyer) review them before signing. Some anomalies carry legal obligations for the buyer from the moment of completion.
What is the DDT?
The DDT is a legally required bundle of condition reports that the seller must provide before you sign the compromis de vente. You receive it, not choose it. The seller commissions and pays for the surveys; you review the results. Not every report is required for every property. Which ones apply depends on the property type (house or apartment), its age, its location, and its energy rating.
These reports do not give the seller a "pass" or "fail." They disclose the condition. In most cases, a poor result doesn't block a sale, but it does affect the negotiation and, in some cases, creates legal obligations for whoever ends up owning the property.
DPE: the energy performance certificate
The DPE (Diagnostic de Performance Energétique) is the most commercially important document in the bundle for buyers on the Côte d'Azur. It rates the property's energy consumption and CO2 emissions on a scale of A to G. A is the most efficient; G is the worst.
The rating matters for two reasons. First, it tells you roughly what you'll spend on heating and cooling. A G-rated property might use four or five times as much energy as a C-rated one of the same size. Second, French law is progressively banning the rental of poorly rated properties.
- G-rated: banned from new or renewed tenancy agreements since January 2025
- F-rated: ban takes effect January 2028
- E-rated: ban takes effect January 2034
If you intend to rent the property, or if you're buying partly as an investment, the DPE rating is not a cosmetic detail. A G-rated villa you plan to put on the rental market is a property you cannot legally rent without significant work. The energy improvement required to move from G to D or C typically costs 15,000-40,000 EUR depending on what work is needed, the property's size, and its construction.
The DPE also shows two numbers: primary energy consumption in kWh per m² per year, and greenhouse gas emissions in kg CO2eq per m² per year. These are theoretical figures based on the building's characteristics, not actual past bills, so they're better for comparing properties than for predicting your exact costs.
If the property is rated F or G and is an individual house, the seller is also legally required to provide an audit énergétique, a more detailed report that shows specific recommended improvement scenarios with estimated costs and the resulting energy class after each scenario. This is worth reading carefully. It tells you what work would need to happen, and at what price, to make the property legally rentable in future.
Diagnostic électricité: electrical installation report
Required for any property where the electrical installation is 15 or more years old, which covers most of the older housing stock on the Riviera. The report checks the installation against NF C 15-100, the French standard for domestic electrical work.
The document lists anomalies in three categories:
- Class 1 anomalies: safety hazards that require immediate attention. These can include absent earthing, live parts exposed without protection, or hazardous positioning of sockets near water. Class 1 findings sometimes lead the surveyor to recommend disconnecting specific circuits.
- Class 2 anomalies: non-conformities that don't present immediate danger but require remediation within a defined period. These are the most common category in older properties.
- Class 3: recommendations that are not legally required.
A report with no Class 1 anomalies and a handful of Class 2 items is common and generally not alarming. A report with many Class 1 anomalies, or where the surveyor has identified an immediate risk to safety, warrants more attention.
The cost to bring an older electrical installation into compliance with NF C 15-100 varies considerably. Updating the consumer unit (tableau électrique), adding RCDs (interrupteurs différentiels), and adding earthing where it's missing: typically 2,000-5,000 EUR. A full rewire of a large villa with work throughout: 10,000-20,000 EUR or more. Get a quote from an electrician before you decide whether to negotiate on price or ask the seller to carry out works before completion.
Diagnostic gaz: gas installation report
Required for properties with a gas installation that is 15 or more years old. The report checks the boiler, pipework, connections, and ventilation of gas appliances against safety standards. The anomaly classification system is the same three-tier structure as the electrical report.
A Class 1 gas anomaly is more serious in practice than a Class 1 electrical anomaly because gas installations can be isolated at the meter without the property losing all services. In some cases, the surveyor will recommend that the gas supply be isolated until the problem is fixed. A property with an immediately dangerous gas installation should not be occupied until it is resolved.
Typical remediation costs range from a few hundred euros for a minor pipework repair to 3,000-6,000 EUR for a full boiler replacement. If the property has a gas boiler you'd plan to replace with a heat pump anyway, a poor gas report may be less commercially significant than it appears.
Diagnostic amiante: asbestos report
Required for buildings where planning permission was granted before July 1, 1997. On the Côte d'Azur, this includes a very large proportion of the housing stock, particularly 1960s to early 1990s construction.
The surveyor checks a defined list of materials and locations: roofing materials (corrugated Eternit sheets were common), floor tiles, insulation around pipework, ceiling coatings, and certain wall materials. The result is either "no asbestos found" (valid indefinitely as long as no works disturb the materials checked), or a list of the asbestos-containing materials with their condition graded:
- State 1: in good condition, no immediate action required; monitor at next check
- State 2: some deterioration, remediation work required within 3 years
- State 3: immediate removal or encapsulation required
Asbestos in good condition is not a health risk and doesn't require immediate removal. The obligation is to monitor it and not disturb it. If you're planning renovation works that would cut, drill, or demolish materials containing asbestos, you need a specialist contractor (and a higher budget). Localized asbestos removal typically costs 1,500-5,000 EUR; extensive removal from a roof or ceiling system can run to 15,000-30,000 EUR.
CREP: lead paint report
Required for buildings built before January 1, 1949. The relevant acronym is CREP, which stands for Constat de Risque d'Exposition au Plomb. This affects older Nice, Menton, and Antibes old town properties, and some of the region's historic village houses.
Lead was used in paint before it was banned. The risk is primarily to children and during renovation works that disturb the painted surfaces. If the surveyor finds lead concentration above the threshold, the seller must disclose it. For sale: if lead is found, the report is valid for one year; if not found, it's valid indefinitely. The required remediation depends on the concentration and location.
Diagnostic termites: termite survey
Required in designated risk zones. Most of the Alpes-Maritimes and the Var are classified as termite-risk zones, which means this report is standard for most property sales in the region.
The surveyor inspects accessible woodwork, floors, and structures for evidence of termite activity. This is a visual inspection, not an invasive one. The report is valid for only six months, so check the date. If termites are found, the property owner is legally required to notify the local mairie and to have treatment carried out. Treatment typically costs 1,500-4,000 EUR for a house, depending on the extent of infestation. Structural timber damage from an established termite problem can cost considerably more to repair.
On the Côte d'Azur, particularly in older houses in the Var and in areas with more woodland, termite findings are not rare. It doesn't make a property unsaleable, but it does require prompt action.
ERP: state of environmental risks and pollution
Required for all properties, valid for six months. The ERP is not a physical survey of the property. It's a disclosure form that maps the property's location against a set of government databases covering natural risks (flooding, earthquakes, landslides, coastal erosion, forest fire), industrial and technological risks, soil contamination, and radon levels.
What to look at: the flood risk zone. Properties in a Plan de Prévention des Risques Inondation (PPRi) zone face higher insurance premiums, restrictions on certain types of work, and occasionally more complex mortgage conditions. The Var river and its tributaries, the lower sections of the Paillon near Nice, and some coastal areas have flood risk designations. Being in a risk zone doesn't mean the property has been flooded, but it's worth understanding before you buy.
Forest fire risk (feux de forêt) is the other category worth checking in inland locations, particularly in the Var and the areas around Grasse and Vence.
Mesurage loi Carrez: floor area (apartments only)
Required for apartment sales, and for units in any collective residential building. The report states the habitable floor area in square metres, calculated according to the rules of the loi Carrez (areas below 1.8 metres ceiling height are excluded, as are garages, cellars, and certain other spaces).
The commercial significance: if the stated area is more than 5% larger than the actual measured area, the buyer has the right to demand a proportional price reduction within one year of completion. In practice, errors in the Carrez measurement do arise, and buyers who have doubts about the stated figure can commission their own independent measurement before signing.
Diagnostic assainissement: sewage system (houses only)
Required for houses not connected to the mains sewage network. Many rural and semi-rural properties in the Alpes-Maritimes and Var use a fosse toutes eaux (septic tank) rather than mains drainage. The assainissement report checks whether the existing installation is compliant with current regulations.
If the installation is non-compliant, the buyer takes on a legal obligation to bring it into compliance within one year of completion. A new compliant installation typically costs 5,000-15,000 EUR depending on the site, the system type, and the access conditions. This is a meaningful cost and should be factored into the purchase price if the existing system is non-compliant.
Using the reports in negotiation
The DDT is provided before you sign the compromis de vente, which is precisely when you should use it. Once you've signed the compromis, you've committed to the purchase at the agreed price, subject only to specific conditions (financing, for example). If you want to renegotiate based on diagnostic findings, you need to do it before signing.
Common approaches:
- Request a price reduction equal to the estimated cost of required remediation works
- Ask the seller to carry out specific works before completion, with a deadline written into the compromis
- For Class 1 electrical or gas anomalies, ask the seller to resolve them before you take possession
- For a non-compliant assainissement, negotiate a specific allowance against the purchase price
Sellers are not legally required to remedy findings in most cases, but buyers can walk away from the compromis on a limited number of grounds. Your notaire is the right person to advise on what leverage you actually have in a specific situation.
Getting help in English
If you're buying on the Côte d'Azur and don't read French, you have a few options. Some notaires in the region offer bilingual services or can arrange certified translations of key documents. There are also independent bilingual property lawyers (avocats or solicitors registered in both the UK and France, in some cases) who can review the DDT and flag anything that needs attention.
For the technical elements, particularly electrical and plumbing, getting quotes from English-speaking contractors before you sign can give you realistic cost estimates to use in negotiation. That's something we can help with. Get in touch if you need a referral to a vetted local contractor for a pre-purchase technical assessment.