Gas Diagnostic Reports in French Real Estate

In French real estate, a gas diagnostic carried out before the sale or rental of a property is crucial to ensure the safety of occupants and the property itself. This diagnostic is regulated by law and must be conducted by a certified inspector.

Type of Property Concerned

The requirement to perform a gas diagnostic depends on the installation’s age, just like the electrical diagnostic. This report is compulsory for any residential property in France with a gas system older than 15 years, regardless of whether it’s for sale or rent. It applies solely to residential buildings and excludes commercial, industrial, office, and other non-residential properties.

Validity Period & Duration

The gas diagnostic remains valid for:

• 3 years in the context of a sale
• 6 years in the context of renting the property

If modifications or repairs have been made to the gas installation, a certificate of conformity issued by an accredited body (e.g., Qualigaz) may replace the diagnostic, provided it is less than 3 years old for a sale or 6 years old for a rental.

Purpose of the Gas Diagnostic

Also known as the Internal Gas Installation Report, this gas diagnostic assesses the safety of gas systems in residential properties. Its main goal is to identify:

• Obsolete equipment
• Installation defects
• Risks such as gas inhalation poisoning, carbon monoxide poisoning, fire, or explosion

For property sales, the gas diagnostic is mandated by Articles L271-4 to L271-6 and L134-6 of the French Construction and Housing Code. It must be included in the Technical Diagnostics File (Dossier de Diagnostics Techniques – DDT), which accompanies the preliminary sales agreement or the deeds of sale.

For rental properties, this diagnostic is required under the ALUR Law (Law No. 2014-366 of March 24, 2014). The report should be attached to the rental lease to inform tenants and ensure access to adequate housing.

Methodology of the Gas Diagnostic

The gas diagnostic follows a methodology established by a decree from the Ministry of Employment, Social Cohesion, and Housing, in conjunction with the Ministry of Industry. It includes inspecting private areas of residential properties, such as annexes in single-family homes. The inspector conducts a visual check of the gas installation downstream from the main shut-off valve, without disassembling any parts.

Inspection Points in a Gas Diagnostic

The diagnostic focuses on the following elements of the gas installation:

• Fixed appliances for heating and hot water production (e.g., water heaters, boilers, radiators)
• Fixed cooking appliances or those using a thermal engine (e.g., cookers, hobs)
• Fixed gas supply pipes, their accessories, and connections to appliances
• Room arrangements, particularly ventilation and the evacuation of combustion products

The diagnostic excludes:

• Appliances supplied by gas cylinders through flexible hoses
• Heating generators with a total nominal power greater than 70 kW for a given room

Actions Required if Anomalies Are Detected

The gas diagnostic does not certify compliance or bring the installation up to standard. However, if anomalies are detected, the following measures apply based on their severity:

• Type A1 anomaly: Minor risk; no mandatory work required, but should be addressed during future maintenance
• Type A2 anomaly: Risk of inhalation or explosion; repairs must be carried out as soon as possible
• DGI anomaly (Immediate and Serious Danger): Critical risk leading to the immediate shutdown of the gas supply. Repairs and compliance work are mandatory before the installation can be reactivated

Consequences of a Non-Compliant Gas Diagnostic

If the gas diagnostic is non-compliant, the report will detail the detected anomalies and the necessary corrective measures. It is recommended to engage a qualified professional to perform the necessary repairs, especially in the context of a sale or rental. Being transparent with the buyer or tenant about the situation is vital to minimise disputes and clarify responsibilities.

Penalties for Non-Compliance

Failing to provide a required gas diagnostic or submitting an invalid report could expose the owner, diagnostician, or notary to liability. Penalties may include:

• Cancellation of the sale or lease
• Payment of damages
• Criminal penalties in severe cases, particularly if there is intent to mislead the buyer or tenant

Examples of non-compliance include:

• Providing false information in sale or rental advertisements
• Using a non-certified diagnostician
• Failing to comply with regulations during the diagnostic process

Difference Between Gas Diagnostic & Maintenance

The gas diagnostic has legal significance in property transactions, whereas annual maintenance does not. While annual servicing is essential for ensuring the proper operation of gas installations, it lacks evidentiary value in real estate dealings. 

In addition, the diagnostic and maintenance procedures follow different inspection protocols and cover separate areas. Maintenance is the occupant’s responsibility (tenant or owner), whereas the gas diagnostic is the property owner’s exclusive responsibility.

Home Insurance and Gas Safety in France

In France, home insurance is mandatory for all residential properties, covering risks like fire, explosions, and gas incidents. Since a gas diagnostic is legally required when selling or renting, it’s crucial to keep your installation safe and compliant. 

Home insurance protects your property and belongings and provides liability coverage for accidents. For peace of mind, visit our insurance page to request a quote and get a personalised offer the same day, ensuring you meet legal requirements while safeguarding what matters most.

For more information about the buying process in France, please visit our complete guide and our popular French blog. Feel free to register to receive property alerts and our monthly newsletters.