Alternative options

1. Obtain a professional valuation 

Estate agents may agree to do an evaluation. In this case it is best to obtain several and take an average. Local notaires can also do this for a fee.

The firm BPCE Solutions Immobilières Crédit Foncier Immobilier - Expertise, a subsidiary of the Banque Populaire Caisse d’Epargne banking group, has a good reputation for giving valuations.

When it comes to independent valuation specialists, a web search will show people describing themselves as experts immobiliers, which can be confusing because the profession is not regulated.

There are around a dozen or so groups which require members to agree to charters of professional ethics and to have professional insurance, which may help indicate a certain level of reliability.

Another option is to look for an expert who is listed by a court as an expert they call on from time to time to advise the judges on technical matters. These take an oath to the court and can be assumed to be well-qualified and reputed.

For example you can find lists of such experts used by the appeal courts (cours d'appel). They are known as experts judiciaires, though technically this only applies when they are called on to do work for the court and it is not a general, official title.

You can find courts operating in your area at this link. You can then do an internet search, such as 'cour d'appel d'Aix-en-Provence experts' and look down the list for ones involved in property (bâtiment or immobilier) and especially estimations immobilières.

2. Re-adjust previous year's values

It is also possible to arrive at a figure by re-adjusting previous values. This is where the previous year’s value is increased by applying a factor such as the national index for the rise in property prices (indice du coût de la construction), available from the national statistics body Insee.

This method is discouraged, however, by the tax authorities as it does not take into account local changes affecting the value. Its use is typically limited to a period of five years.

3. Add up the costs

Where you have had the property built, you could take the total cost of construction and furnishing, then multiply by an appropriate factor to arrive at the probable current value, then apply a discount for age and wear and tear of comparable properties. This is an uncertain method since factors for this are not published.

A comparable method for a property you did not build involves ascertaining the cost of rebuilding and refurbishing but this can be uncertain. You would need to pay an architect for estimates.

4. Expert help for rental properties

Where residential property is rented out on a long-term lease, the market value can be obtained using a calculation involving the annual rent and a figure called the taux de capitalisation, which depends on the type of building and its characteristics. You will usually need an expert to work out this value for you.

5. Property owned under an SCI

Property owned under a société civile immobilière (SCI) is declared based on the value of the shares held if you were to sell them (known as the valeur vénale) to the level of the proportion of the value that is represented by property (as opposed to eg. money in a bank account or other assets).

The total value of the shares is multiplied by a coefficient obtained by dividing the value of 'property assets' by total assets.

Certain debts of the SCI related to the taxable property assets can be deducted from the total value before the coefficient is applied.

Some SCI shares such as those that relate to property used professionally by the taxpayer can be exempt.

6. Other points

• Building land needs to be evaluated at the market price, assuming it meets usual criteria such as the possibility of obtaining planning permission or the availability of utilities. If work has begun on it the estimate should account for the stage this is at, which may require a professional.

•  For agricultural land, the Ministry of Agriculture has price data which can help and the Safer professional farming organisations also have data (also on le-prix-des-terres.fr). For woods you can use figures from the Safers or the Société Forestière.

• In certain cases, company shares may have a declarable element in proportion to property owned by the company, in which case shares would usually be valued at the last known valuation on January 1, 2025.

•  As a general rule properties for which you own the usufruit (lifetime right to use/rent out etc) are declarable for the full amount, with certain exceptions.

• Properties you only own for the residual legal right of nue-propriété are exempt