Complete Guide to Diagnostic Technique Global (DTG)

If you own or manage a co-owned property (copropriété) in France, the Diagnostic Technique Global (DTG) is a tool you should be aware of and understand.

More than just another diagnostic, the DTG is a complete health check for your building. It assesses the condition of common areas, evaluates energy performance, and outlines the essential repairs and their estimated costs for the next decade. This ensures that your French property remains in good condition while helping co-owners plan, budget and avoid unexpected expenses.

But when is the DTG required, and how can it benefit your co-ownership? 

What is the DTG?

The DTG (Diagnostic Technique Global) is a detailed technical assessment designed for co-owned residential buildings. It provides a comprehensive overview of the property’s condition, including common areas such as hallways, stairwells, roofs, and facades, as well as safety equipment such as fire alarms and emergency exits.

Additionally, the DTG includes an energy performance evaluation, either through a collective Diagnostic de Performance Énergétique (DPE) or a full energy audit. It also offers a financial snapshot of the co-ownership association (syndicat de copropriétaires), including its budget and reserves.

Finally, the DTG provides a 10-year maintenance plan that lists the mandatory repairs and their estimated costs. This allows co-owners to anticipate expenses and prioritise repairs effectively.

When is the DTG Mandatory?

The DTG is legally required in two specific scenarios.

• when a building over 10 years old is converted into a co-ownership. For example, if an apartment building was constructed in 2014 and is being divided into private lots and common areas in 2025, a DTG must be completed before the conversion.
• when a building is subject to an insalubrity (unsanitary conditions) procedure at the request of local authorities.

For existing co-ownerships, the DTG is not mandatory but is highly recommended. The syndic (property manager) or any co-owner can propose its inclusion in the agenda of a general meeting (Assemblée Générale).

If approved by vote, the DTG can then be commissioned. Once completed, the DTG often serves as the foundation for a Multi-Year Work Plan (Plan Pluriannuel de Travaux, or PPT), helping co-owners plan and budget for future repairs.

Who Can Perform a DTG?

The DTG must be carried out by a qualified professional with expertise in building construction methods, technical equipment and systems, and construction materials. This could be a building surveyor, architect, or thermal engineer.

However, the professional must also meet specific criteria. They must declare their impartiality and independence from the syndic, energy suppliers, and any companies working on the building. Additionally, they must hold professional liability insurance that explicitly covers the DTG’s scope of work.

How Much Does a DTG Cost?

The cost of a DTG varies significantly with the building’s size and complexity. Typically, the price ranges between €1,000 and €15,000 for the entire building, with most co-ownerships paying between €9,000 and €10,000 (including VAT). As prices are not regulated, it is wise to compare quotes from multiple providers before making a decision.

Who Pays for the DTG? Can it be Funded?

The DTG is considered a general common expense, meaning its cost is shared among all co-owners based on their tantièmes (or millièmes), which are the ownership shares that determine each co-owner’s contribution to common expenses.

There are funding options available to help cover the cost. The co-ownership can use the mandatory work fund (fonds de travaux obligatoire), introduced by the Alur Law, specifically designed to cover the costs of diagnostics and repairs.

Additionally, some municipalities or metropolitan areas offer subsidies through local energy agencies or platforms like France Rénov’ to encourage energy-efficient upgrades in co-ownerships.

How is the DTG Controlled?

Local authorities, specifically the Maire or Préfet, can request a DTG from the syndic if the building shows signs of health hazards for occupants or neighbours, serious dysfunctions or lack of maintenance that compromise living conditions, or structural risks, such as the threat of collapse or unsanitary conditions.

If the syndic fails to provide the DTG within one month of the request, the Maire or Préfet can order the DTG to be carried out at the co-owners’ expense.

Why the DTG Matters: Practical Benefits

The DTG isn’t just a legal formality; it’s a powerful tool for co-ownerships. It provides transparency for property investors, as the DTG report must be provided to the buyer and included in the compromis de vente if a co-owner sells their unit. This ensures full transparency about the building’s condition and future expenses.

The DTG also enables financial planning, as its 10-year repair plan allows co-owners to budget effectively, avoid unexpected costs and expensive surprises. By identifying issues early, the DTG helps extend the building’s lifespan and improve its value. In addition, the energy audit component (DPE) highlights opportunities to reduce costs and environmental impact.

Is a DTG Right for Your Co-Ownership in France?

If your building has been newly converted to co-ownership or is facing insalubrity issues, the DTG is non-negotiable. For existing co-ownerships, it’s a smart investment, one that can save money, prevent disputes and enhance property value in the long run.

Next steps:
Check your building’s age and status. If it’s over 10 years old and being converted into a co-ownership, a DTG is required. Discuss it at your next general assembly. Even if it’s not mandatory, the DTG can provide clarity and peace of mind to all co-owners and future buyers. Consult a certified surveyor or architect to get a quote for your DTG.

For more information about owning a property in France, please take a look at our expert guides on our French blog. And feel free to register to receive property alerts and our monthly newsletters.