Land is compulsorily purchased to form a land reserve (réserve foncière, land held by a public body for future development), then stays frozen for more than thirty years. The successors of the former owners apply for retrocession (rétrocession, the former owner’s right to buy back unused expropriated land), run into a new declaration of public utility and claim, instead of the land, the added value they lost. In a decision of 12 March 2026, the Third Civil Chamber of the Cour de cassation (the French supreme court for civil matters) approved the Court of Appeal that dismissed that claim: lost added value is compensated only if no reason of public utility justifies the failure to carry out the operation. For the valuer, the planning chronology weighs as much as the figure.
The facts
By an order of 15 November 1989, several plots were compulsorily purchased for the benefit of the département of La Réunion (the county-level authority) to form a land reserve for housing in one of its municipalities. According to the Court of Appeal’s reasons quoted in the appeal, the planned reserve covered several dozen hectares of land that was unbuildable in 1989.
On 22 November 2017, eighteen successors of the former owners (the expropriated parties) applied for retrocession of the land. Article L. 421-1 of the French Expropriation Code opens that right where the property has not received its intended use within five years of the order, for thirty years, unless a new declaration of public utility (déclaration d’utilité publique) is requested. The département requested one on 24 March 2021, and the Saint-Denis tribunal judiciaire (first-instance civil court) dismissed the retrocession application.
The expropriated parties then sued the département for compensation for the lost added value. On 29 April 2024 the Saint-Denis Court of Appeal dismissed the claim. According to its reasons quoted in the appeal, buildability lay with the municipality, which only began amending its local planning plan (plan local d’urbanisme, PLU) in 2011.
The expropriated parties appealed, relying on article L. 421-1 and on the right to the peaceful enjoyment of possessions (article 1 of Protocol No. 1 to the European Convention on Human Rights): in their view, only a reason of public utility behind the failure to use the land could defeat their right.
The decision
The Cour de cassation dismissed the appeal (Cass. 3e civ., 12 March 2026, appeal no. 24-17.000, unreported).
It first held that the Court of Appeal had “correctly restated” two principles (translated from the French). First, “the purpose of constituting land reserves is to freeze land over time, no time limit being set for allocating it to a development project meeting a requirement of public utility”. Second, “where the value of the expropriated land has increased since the date of expropriation, while no reason of public utility justifies the failure to carry out the planned operation, the former owners are entitled to seek compensation for the excessive burden suffered as a result of a loss of added value”.
It then approved their application to the case. In the Court’s words, the Court of Appeal had found that the length of the procedure to amend the local planning plan, “begun in 2011 and completed on 21 February 2017 with the approval of a new land-use plan changing the designated use of the expropriated plot”, justified the operation not being carried out during the period between the expropriation and the request for a new declaration of public utility. That new declaration concerned “new development projects consistent with the changes in the authority’s powers, linked to the initial declaration of public utility, justified by demographic pressure and the shortage of available land”. The Court of Appeal had therefore, “on those grounds alone, provided a legal basis for its decision”.
The Court did not rule on the fraud or speculation requirement that the appeal accused the Court of Appeal of applying. On the same day, it decided another compulsory purchase question: Compulsory purchase: post-notice works held not speculative.
What this changes for valuation
Two conditions, only one of which is quantified. The increase in value since expropriation is a valuation matter: value at the date of expropriation, under the zoning of the time, then value at the comparison dates the judge will adopt, since the decision fixes only the starting point. The absence of a public-utility reason justifying the delay is for the judge, but turns on facts the report can establish.
The planning chronology, document by document. Here the Court relies on two points found by the Court of Appeal: the length of the local planning plan amendment, from 2011 to 21 February 2017, and the link between the new declaration, requested on 24 March 2021, and the first. The valuer gathers the plans, council resolutions and orders of each period, dates the change of zoning, sets the new declaration against the first and checks the land’s occupation at each date adopted, since it weighs on value.
Measuring, once the principle is established. The decision says nothing about measurement, since it rules out the indemnity. A reported decision of 10 July 2025 concerns a different situation: the right of retrocession had been recognised, then return of the land had become impossible, which was resolved by damages; the loss of added value ran from the summons for retrocession to the day the right was definitively recognised, not from the expropriation: Retrocession impossible: added value between two dates. In 2026, by contrast, retrocession had been refused after a new declaration of public utility; the indemnity required a rise in value since expropriation with no public-utility reason justifying the delay, and the decision does not say over what period it would be measured. The report then presents the values at the dates the parties are debating.
A public purpose kept or abandoned. After a délaissement (an owner’s purchase notice on reserved land), the Court held excessive the interference with the property rights of the owner’s successor, left without any compensation although the municipality had rezoned the land as buildable and resold it without keeping its public-interest purpose: Reserved land surrendered then resold buildable: lost gain owed. Here the decision mentions no resale: the acquiring authority requested a new declaration linked to the first. If the compulsory purchase is annulled, a different formula applies: Annulled compulsory purchase: lost added value when return fails.
What the valuer takes from it
- Land frozen in a land reserve has no deadline for its use: here, more than thirty years of waiting did not, on their own, open a right to the lost added value.
- Compensation requires a value that has risen since expropriation and no reason of public utility justifying the failure to carry out the operation.
- The report rebuilds the chronology of planning and of the declarations of public utility, documents in hand: here, the judge assessed the delay on these facts.
- Each value is set under the zoning and market of its date; the bounds of the decision of 10 July 2025 concern the distinct case of a retrocession recognised and then made impossible.
Further reading
The Compulsory purchase and pre-emption page describes the assignment and its fee. The guide Pre-emption by a public body in France: setting a defensible price and the glossary entries declaration of public utility (déclaration d’utilité publique), compulsory purchase (expropriation) and valuation date (date de valeur) complement this article. Two related decisions of March and April 2026 are discussed separately: Compulsory purchase: post-notice works held not speculative and Expropriated co-ownership lot: common parts are in the m² price. On the same theme: Retrocession impossible: added value between two dates and Pre-empted land resold: no lost added value for the seller. The decision is available on Légifrance.
What next
Land frozen in a land reserve, a retrocession refused and added value in dispute?
I rebuild the chronology of the planning documents and declarations of public utility, then establish the value of the land at the dates in dispute, each under the zoning and market of its time, in a report fit for use 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).
