To reassess the declared value of a property, the French tax authority cites sales of properties it considers comparable. Is it enough that those properties have a large living area, a swimming pool and a similar standing, if the size of their plots is unknown? No, the Commercial Chamber of the Cour de cassation (French supreme court for civil and commercial matters) held on 25 January 2023: the area of the land is one of the criteria of value, and comparables that do not state it cannot establish their similarity with the property.
The facts
On 8 March 2007 an individual bought, from an SCI (société civile immobilière, a French property-holding company) of which he was the manager, a group of properties in Mandelieu-La Napoule including a villa. The tax authority considered insufficient both the acquisition value declared for that villa for registration duties and the value he had declared for the impôt de solidarité sur la fortune (ISF, the French wealth tax replaced by the IFI in 2018). It served two tax reassessment notices (propositions de rectification) on him: one for additional registration duties, the other for additional ISF for 2008 and 2009.
The departmental conciliation commission (commission départementale de conciliation) reduced the market value initially adopted, and the tax authority followed its opinion. The taxpayer nevertheless sued the tax authority for discharge of the duties claimed. A judgment of 26 October 2016 dismissed his claims; the Aix-en-Provence Court of Appeal, after a first decision of 3 July 2018, upheld it on 5 November 2019.
According to that court, the villa, of 392 m², stands on a 2,925 m² plot and comprises fifteen main rooms, six bathrooms, a garage and a 90 m² swimming pool; it has the features of a luxury villa. The court adopted the value of €5,026 per square metre proposed by the commission on the basis of five of the eight comparables put forward by the tax authority: villas of 200 to 423 m² of living space, with many main rooms and a swimming pool, of a similar standing, “notwithstanding the absence of any detail as to the area of their respective plots” (translated from the French), and in the same or a lower cadastral category (the classification used for local property taxes). It concluded that these comparables “are consistent with the property in question”. The taxpayer appealed to the Cour de cassation against both decisions.
The decision
The Cour de cassation quashed the decision of 5 November 2019 in all its provisions and referred the case back to the Aix-en-Provence Court of Appeal, differently composed (Cass. com., 25 January 2023, appeal no. 20-16.125, unreported). It also declared the appeal lapsed (déchéance) as regards the decision of 3 July 2018.
Under article L. 17 of the French Book of Tax Procedures (Livre des procédures fiscales), it recalled that the tax authority “may reassess the price or the valuation of an asset that served as the basis for levying a tax where that price or valuation appears lower than the real market value of the assets transferred or described in the deeds or returns, that real market value having, as a rule, to be established by the comparison, at the time of the taxable event, of intrinsically similar properties” (translated from the French).
It then held that the Court of Appeal had relied “on grounds unfit to establish that the properties used as comparables were intrinsically similar to the property in dispute, since the area of the land of a property is one of the criteria for determining its value”. The Court of Appeal “did not give a legal basis to its decision”.
The Court does not say that the value of €5,026 per square metre is wrong, nor that comparables must have a plot of the same size: it censures reasoning that concludes there is similarity without knowing that criterion. It dismissed the first and fourth limbs of the ground of appeal without specific reasoning (article 1014, paragraph 2, of the French Code of Civil Procedure), did not rule on the last complaint and gave reasons for quashing only on the area of the land.
What this changes for valuation
Similarity is demonstrated feature by feature. According to the Court of Appeal, the comparables had a large living area (200 to 423 m²), many main rooms, a swimming pool, a similar standing and the same or a lower cadastral category. The area of their plots was not stated. A plot of almost 3,000 m², like the villa’s, can carry a garden, privacy, the setting of the pool and sometimes room for an extension: a comparison that ignores the land compares only part of the property. Pre-emption cases set a similar requirement on zoning (comparables subject to the same planning rules).
A price per square metre includes the land without measuring it. The commission reasoned in euros per square metre, on villas chosen for their living area. Two 300 m² villas, one on 800 m² of land and the other on 3,000 m², have no reason to sell at the same price per square metre. Applying to the villa a ratio drawn from comparables whose plot is unknown amounts to assuming, without checking, that the plots are equivalent. The Charte de l’expertise en évaluation immobilière (French property valuation charter, 6th edition, November 2025) states that “the prices observed are adjusted to take account of the differences between the reference properties and the property valued” (translated from the French; Title III, § 2.1.1). An unknown difference cannot be adjusted.
For the taxpayer, a method of reply. In tax matters, “the tax authority favours the comparison method”, the Charter notes (Title II, § 8.14). A reply to a reassessment notice therefore takes each comparable cited in turn: date, address, living area, plot area according to the deed or the land register, condition, category. The taxpayer’s own report is open to the same reading: its references are described down to the land and its adjustments reasoned, as explained in the article on what a valuation report contains.
Two neighbouring but distinct questions. On 19 June 2024 the same chamber held that the price of a resale after the death does not replace the value on the date of the transfer: a question of date, not of similarity (Inheritance tax: a later resale does not fix the value at death). On 6 May 2026 it dismissed the appeal of taxpayers who had not established the singular character of their property, capable of justifying a departure from valuation by comparison (building land with environmental constraints). These solutions combine: comparison remains the principle and, when the tax authority uses it, its comparables must be intrinsically similar to the property, land included.
What the valuer takes from it
- A comparable is described in full: date, location, living area, plot area, condition, category.
- The area of the land is a criterion of value; without it, the similarity of a comparable is not established.
- A price per square metre is carried over to the property only after correcting the differences in plot.
- The decision fixes no value and does not require identical plots: it requires the plot area of the comparables to be known before their similarity can be established.
Further reading
The Market value page describes the assignment, its timescale and its fee. The guide French wealth tax (IFI): what value to declare for my house and SCI? and the glossary entries comparable, comparison method and market value complement this article. On the valuation date, a distinct question: Inheritance tax: a later resale does not fix the value at death. On the same theme: Disguised gift: French tax reassessment of a family sale and Inheritance: undervaluing is not, in itself, a deliberate breach. The decision is available on Légifrance.
What next
A tax reassessment notice based on comparables?
I examine the comparables put forward by the tax authority one by one, land included, and I establish the market value of the property on the date of the taxable event. The report serves for the reply to the reassessment notice, before the conciliation commission or before the court.
Free quote, by email or by phone. No commitment before the quote is accepted. Fees are never linked to the value of the property (Charte de l’expertise, Title I, §2.1).
