As the owner/vendor or landlord of an apartment or detached house, you must provide the prospective purchaser or tenant with a gas diagnosis if the facility has over 15 years.

The gas diagnosis must be carried out by a diagnoser meeting certain criteria, in particular certification.

This person must have purchased a assurance to cover the consequences of liability arising from its operations. It must not see any link that could affect its impartiality and independence vis-à-vis you or your agent who calls on it, or with a company that can carry out work on the works, installations or equipment. 

You can use a directory to find a certified diagnoser:

Find a Certified Real Estate Diagnoser

Gas diagnosis is done in private parts of the accommodation and the outbuildings.

It shall describe the following information:

• Condition of fixed gas-fired heating and hot-water appliances or of fixed gas-fired heating and hot-water appliances
• Condition of fixed gas supply pipes and accessories therefor
• Provision of rooms in which gas appliances operate, allowing ventilation of these rooms and evacuation of combustion products.

The gas diagnosis must be carried out in accordance with regulated model and method.

You need to integrate gas diagnostics with the various real estate diagnostics included in the Technical Diagnostic Record (DDT) in case of sale or in case of rental.

DDT should be delivered:

• At future purchaser at the time of signature of the promise of sale or the authentic instrument of sale
• Or at prospective tenant at the time of signing the lease.

The period of validity is different in the case of sale or rental.

Sanctions vary depending on who is involved.