Public data and tools

Valuing your property is key to working out your eligibility for IFI – and how much tax you should pay.

Everything forming part of your declarable property estate has to be valued at its market rate as of January 1, 2026.

There are several established methods – some free, others not – to use.

The law refers to the market value, although this can sometimes be difficult to ascertain, particularly for remote properties, or ones which do not resemble neighbouring ones.

Fortunately, in recent years official data from the tax office and notaires has improved and there are now various tools to help – we list four key one here:

1. The notaires' property website immobilier.notaires.fr offers a helpful carte des prix au m2 (map of prices per m2) where you can see what properties have been selling for recently in a given area by zooming into a map (use the mouse wheel if on a desktop computer).

You can narrow down the search by number of rooms, whether the property is new-build or not, and whether or not it has a parking space.

‘New-build’ (neuf) in this sense refers to properties built within the last five years. All other property is described as ancien.

2. The notaires have another price site at leprixdelimmo.notaires.fr which in theory allows for a search with more specific criteria although it is less user-friendly.

3. The government data map is also helpful. You can see specific sales including the type of property and size, sale date and price, using tax office information. An alternative, also from the government, is app.dvf.etalab.gouv.fr.

4. The tool Patrim can be used by anyone who has an account on the tax website impots.gouv.fr. Once logged in go to Autres services then Rechercher des transactions immobilières. The opening page (see image on page 21) asks you to state the reason for using it (ie. déclaration d'IFI).

It uses tax office records on recent property sales and can help you estimate the value of a home by seeing what comparable properties sold for recently. You need to give details such as type of home (eg. house or flat), floor space, location etc. It will provide a list of sales in the geographical area and time period you specify.

Haut-Rhin, Bas-Rhin, Moselle or Mayotte departments are not covered.

The above services should be used as a guide and you must also take account of your property’s particular amenities, location and quality.

Take into account all factors

The common way to evaluate is by comparing your property to similar ones taking into account factors such as the ground area of the building, surface area on all floors, surface areas developed for use, the amount that is habitable and the number of rooms.

You should also consider the quality of materials and architecture, the condition of the property, where it is located and the level and standard of equipment.

Legal factors may also come into play –for example, the length of a lease, servitudes, restrictive covenants and local development restrictions.

Occupational factors also count. A property you rent out would be valued at less than one you have the right to occupy.

Note that the reduction will be lower where the home is rented out furnished because it is easier to end the lease compared to unfurnished lets.

A property occupied by a tenant would typically be eligible for a 20% reduction (probably more, for example in the case of a commercial lease where the tenant has a right to remain).

Similarly, property held in joint ownership with other people may be subject to a reduction of between 10% and 20% in value accounting for the increased difficulty you would have in selling it.

In the case of properties rented out as someone's home, the reduction generally depends on the type of lease and local property market. The reduction will be greater for a long lease and if there is a scarcity of local rental property making it harder to take back the property from the tenant.

However, the requirements to rent out a property for a given time in the context of certain tax breaks for buy-to-let property do not give rise to increased reductions.

Property rented out on very long-term leases (bail emphytéotique) is reduced in value in proportion to the time left on the rental period, taking into consideration factors such as the level of the rent and whether there are buildings that are the responsibility of the tenant but will remain your property at the end of the rental.

People who own a listed historic monument may take into account the extra responsibilities involved for this, such as, potentially, opening it to the public, or high maintenance costs.

Remember that property that is used by the owner on January 1, 2026, as their main private residence is entitled to an automatic deduction of 30%.

Where families live in France in more than one property only one can be deemed the principal home and thus entitled to the reduction.