Three dismissals by the third civil chamber of the Cour de cassation (the French supreme court for civil matters), handed down in March and April 2026, shed light on three questions a valuer meets in almost every compulsory purchase file: do works carried out by the owner shortly before dispossession count in the indemnity, how is a co-ownership lot valued with its share of the common parts, and what becomes of the added value of land frozen in a land reserve for thirty years. None lays down a new rule; all three show what the court expects by way of demonstration, and therefore what the valuation report must contain.
Works carried out under a safety order: not speculative
A property company is compulsorily purchased in Marseille of a built plot by the company Marseille habitat. Between late 2019 and 2021 it renovated the building: joinery and facade, but also room layout, wiring, finishes, shower cubicles. The acquiring authority argues that these works were done “with the aim of obtaining a higher indemnity” within the meaning of article L. 322-1 of the Expropriation Code, that they exceed what the administration had prescribed, and that they were carried out without planning permission, in a heritage zone and in breach of a social-mix easement.
The Aix-en-Provence Court of Appeal, on 7 March 2024, takes them into account in the indemnity, and the Cour de cassation approves (Cass. 3e civ., 12 March 2026, no. 24-16.458): the works “carried out following an order issued on 1 October 2019 by the risk prevention and management directorate of the city of Marseille under threat of a non-imminent danger order, followed major structural works authorised and carried out in 2006 and 2007, whose durability had been confirmed in January 2019 by an engineering firm”, so that the Court of Appeal “could infer, within its sovereign power, without being required to make inquiries that its findings rendered pointless, that the works undertaken from the end of 2019 were not of a speculative nature”.
For the valuer, the lesson is one of method. The statute presumes speculative, unless the contrary is proved, improvements made after the opening of the public inquiry, and the court sets aside those whose timing or circumstances reveal their aim. The contrary proof is made by chronology and documents: the administration’s order, earlier permits, the engineering report, the invoices. The valuation report rebuilds that chronology, separates what was prescribed from what was added, and values the property in its condition at the reference date, works included where they are justified. Planning compliance is a separate question, that of the unlawful building, which the ruling did not have to decide.
Co-ownership lot: the Carrez square metre carries the shares
A company is compulsorily purchased of a lot in a co-owned building, by a Greater Paris development agency. Besides the indemnity for its private lot, it claims a separate indemnity for its share of the common parts, a plot of 6,177 m², arguing that its shares allowed it to oppose any disposal and that the co-owners’ association had not been compensated. The Paris Court of Appeal, on 21 March 2024, refuses: the land within the common parts has no intrinsic value and cannot be valued separately.
The Cour de cassation dismisses the appeal (Cass. 3e civ., 9 April 2026, no. 24-16.638): “the Court of Appeal noted that the surface area of the expropriated party’s private lot was measured in Carrez-law square metres, to which the shares of common parts were attached”, and, “retaining the valuation method it found most appropriate, it fixed within its sovereign power the price per square metre of the private lot taking into account the extent of the common parts”.
That is valuation practice in co-ownership: the lot sells per square metre of private floor area, and that price includes the common parts, garden, parking, service rooms, whose extent justifies a higher unit price than a comparable lot without those amenities. The report does not show two lines, lot and share of land, but a price per square metre supported by comparables and, where the common parts are exceptional, an explained adjustment. The article on valuing the common parts of a building and the one on the pre-emption of a lot whose common parts are dilapidated deal with cases where that adjustment works upwards or downwards.
Land reserve and added value: public interest can justify everything
Plots are compulsorily purchased in 1989 by the department of La Réunion to form a land reserve for housing. They were not buildable. In 2017 the heirs of the former owners apply for retrocession, the land not having been used; the department requests a new declaration of public utility in 2021, which defeats the retrocession. The former owners then claim compensation for the added value the plots have gained, having become buildable after the local plan was modified in 2017.
The Saint-Denis Court of Appeal, on 29 April 2024, rejects the claim, and the Cour de cassation approves (Cass. 3e civ., 12 March 2026, no. 24-17.000). It first recalls the principle, both ways: “the purpose of land reserves is to freeze land over time, no time limit being set for assigning it to a development project meeting a requirement of public utility”, and “where the value of the expropriated land has increased since the date of expropriation, while no reason of public utility justifies the non-completion of the planned operation, the former owners are entitled to seek compensation for the excessive burden suffered through a loss of added value”. Here, the length of the procedure to modify the local plan, begun in 2011 and completed in 2017, and the new declaration of public utility, “linked to the initial declaration, justified by demographic pressure and the shortage of available land”, justified the non-completion.
The indemnity for lost added value therefore exists, but it requires that nothing of public utility explains the delay. When it is in dispute, the valuer establishes two values: that of the land at the date of the summons for retrocession, in its zoning of the time, and that it had at the date the right of retrocession was definitively recognised, with its new zoning, services and the market of that moment. Those are the two bounds set by the ruling of 10 July 2025 on impossible retrocession, not the date of expropriation nor that of the judgment. The gap is the added value the former owner was deprived of; the judge then decides whether the acquiring authority answers for it. Without that double valuation, the claim has no figure.
What these rulings have in common
In all three cases the Cour de cassation defers to the sovereign assessment of the trial courts on questions of fact: the cause of the works, the method of valuing the lot, the justification for the delay. Everything is therefore decided before the Court of Appeal, on the documents. The valuation report produced by the expropriated party, or by the acquiring authority, carries all the more weight when it documents the chronology, explains the method and presents the alternative values the judge might retain.
- Works done after the opening of the inquiry are not speculative where an order of the administration required them; the report supplies the proof.
- A co-ownership lot is valued per Carrez square metre, shares included, with no separate indemnity for the share of the common parts.
- The lost added value of land frozen in a land reserve is compensated only if no reason of public utility explains the delay; it is quantified by two values, at the summons for retrocession and at the definitive recognition of the right.
Further reading
The Compulsory purchase and pre-emption page describes the assignment, its timescale and its fee. The guide My business premises are compulsorily purchased and the glossary entries indemnité principale, date de référence and surface Carrez complement this article. On the same theme: Compulsory purchase: three recent rulings and Compulsory purchase: completed works and cellars in the indemnity. The decisions are available on Légifrance: no. 24-16.458, no. 24-16.638 and no. 24-17.000.
What next
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