A plot reserved for a cemetery extension carries buildings partly erected without planning permission. Its owners serve a purchase notice (délaissement, the right to require a public body to buy land reserved for a public project), and the expropriation judge (juge de l’expropriation) sets the price. If the action for demolition is time-barred, must these buildings be paid for as if they were lawful? In a reported decision of 9 November 2023, the Third Civil Chamber of the Cour de cassation (the French supreme court for civil matters) accepts a discount (abattement) for the unlawfulness of the buildings, even where demolition can no longer be sought, without referral to another court.
The facts
Joint owners held a plot burdened by a reserved site (emplacement réservé, land earmarked in the planning document for a future public facility) for the extension of the municipal cemetery. They served a purchase notice on the municipality, which benefits from the reservation. Failing agreement on the price, the municipality asked the expropriation judge to order the transfer of ownership and set the price.
On the lawfulness of the buildings, the owners relied on a building permit application of 5 July 1985, covering in their view a detached house and the creation of 974.50 m², and on a certificate from the mayor referring to a tacit permit of 17 February 1986 for the extension of an existing building. In a judgment of 5 May 2022, the Aix-en-Provence Court of Appeal found, on the basis of a report, that a significant part of the buildings did not appear in the 1985 application. It concluded that part of the buildings was unlawful and applied a discount to the value of the property. The Cour de cassation’s decision mentions neither the rate of that discount nor the price set.
The judgment was challenged by a main appeal, dismissed without specific reasoning, and by the owners’ cross-appeal (pourvoi incident). In their view, the lawfulness of the buildings was a difficulty unrelated to fixing the compensation, which required the judge to set alternative awards and refer the parties to the competent court (article L. 311-8 of the Expropriation Code, code de l’expropriation); the burden of proof lay on the municipality; and the Court of Appeal, having found that the ten-year time bar prevented any action for demolition, could not apply a discount.
The decision
The Cour de cassation dismissed the appeals (Cass. 3e civ., 9 November 2023, appeal no. 22-18.545, reported decision).
On the serious dispute (contestation sérieuse), the Court answered: “The court of appeal, which found that, in the light of the documents produced, a significant part of the buildings on the plot subject to the purchase notice had been erected without a building permit, could deduce from this, without deciding a serious dispute, that a discount should be applied to the value of the property to take account of the unlawfulness of the buildings” (translated from the French, as are all quotations below).
On proof, it noted that the Court of Appeal had found, without distortion, that it emerged from the report that a significant part of the buildings “did not appear in the building permit application filed in 1985”, and then that it “deduced, in the exercise of its sovereign assessment, from that ground alone, without reversing the burden of proof, but by analysing all the documents produced, that part of the buildings was unlawful”.
Finally, on the time bar: “It could conclude that this situation constituted a loss of value justifying a discount for unlawfulness of the buildings, even if the action for demolition were time-barred.”
The Légifrance summary cites article L. 230-3 of the Planning Code (code de l’urbanisme), on purchase notices, and article L. 321-1 of the Expropriation Code, on full compensation for the loss. The word “could” leaves the discount to the trial judges (juges du fond): the Court accepts it without requiring it or setting its level.
What this changes for valuation
The time bar protects against demolition, not against loss of value. The Court allows the unlawfulness to be treated as a loss of value (moins-value), even without any risk of demolition. A partly unauthorised building is harder to sell and to alter, and the buyer prices in that uncertainty: the report therefore does not treat the time bar as regularisation. Until the time bar runs, the risk is heavier: demolition may be ordered, even in summary proceedings (référé), as in a decision of 25 June 2026 on unauthorised installations in a natural zone.
Comparing what exists with the permits. The decision rests on a factual comparison between what was built and what the 1985 permit application covered, from which the Court of Appeal deduced the unlawfulness. The valuer lists the buildings and floor areas, gathers permit applications, orders, declarations and plans, and establishes, building by building, what is authorised or not; the report flags what has not been evidenced.
Quantifying the discount. As the decision gives no rate, the discount is reasoned by what an informed buyer would deduct: the weight of the unlawful floor areas in the total value, the cost and feasibility of regularisation where the planning rules allow it, restrictions on use or works, a longer resale period. The report values the property, then justifies the discount rather than stating a bare percentage.
No alternative awards. Where a serious dispute concerns the merits of the right, the expropriation judge sets alternative awards and refers the parties to the competent court. Here, the judge applies the discount directly, the unlawfulness emerging from the documents: the report must evidence it and give a reasoned figure.
Two decisions that fit together. On 15 February 2024, the same chamber held that an unlawful building on an unbuildable plot gives no right to any compulsory purchase compensation, in the absence of a legally protected right, even if any action for demolition is time-barred. The 2024 decision does not contradict the 2023 ruling: in both cases, the time bar on demolition does not prevent the unlawfulness from being taken into account, and once found, it does not call for alternative awards. On an unbuildable plot, the 2024 decision goes further and its solution applies: the unlawful building is not compensated at all, instead of being discounted; in the 2024 case, where it was the only building on the plot, compensation was set at the bare land value. The 2023 decision does not state the planning rules applicable to the plot; on buildable land, the report quantifies the effect of unlawfulness building by building. A building declared irremediably unfit for habitation falls under a different rule, discussed with the decision of 13 April 2023.
What the valuer takes from it
- Even if the action for demolition is time-barred, the unlawfulness may constitute a loss of value justifying a discount.
- The expropriation judge may apply that discount on the basis of the documents, without setting alternative awards.
- Unlawfulness is shown by comparing the existing buildings with the permits produced; the report states what has not been evidenced.
- The decision sets no rate: the discount is quantified and reasoned by what the unlawfulness costs a buyer.
- Before quantifying the discount, the report checks that the plot is buildable; otherwise, under the decision of 15 February 2024, the unlawful building is not compensated.
Further reading
The Compulsory purchase and pre-emption page describes the assignment, its timescale and its fee. The guide Pre-emption by a public body in France: setting a defensible price and the glossary entries abattement, moins-value and juge de l’expropriation complement this article. On another point decided in 2023: Irremediably insanitary building: bare land value applies. On the same theme: Compulsory purchase of an unlawful building: no compensation due and Reserved land surrendered then resold buildable: lost gain owed. The decision is available on Légifrance.
What next
Buildings without a permit on land subject to a purchase notice or a compulsory purchase, and a price to establish?
I compare the existing buildings with the permits produced, building by building, then quantify the value of the property and the discount justified by the unlawful part, with references, for the owner as well as for the public body.
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