A couple buys a building plot in March 2012. The risk statement attached to the promise of November 2011, then to the deed, mentions a flood risk prevention plan that has been prescribed. Between the two, on 28 February 2012, the plan was approved. Four years later the municipality issues them a negative planning certificate: the plot lies in a very high hazard zone, no house can be built there. The Court of Appeal rejects their claim: the information was the same. On 19 February 2026 the Cour de cassation (the French supreme court for civil matters) quashed that ruling, in a published decision: an approved plan is a public-interest easement, and the risk statement had to be updated at the deed. The buyer may then seek rescission of the sale or a reduction of the price, and that is where valuation comes in.
The facts
By a bilateral promise of 3 November 2011, then a deed of 21 and 23 March 2012, two sellers transfer a building plot to a couple. A natural risk statement (état des risques) dated 3 November 2011, still valid at the deed as less than six months old, is attached to both instruments; it states that the plot lies within the perimeter of a flood risk prevention plan prescribed by order of 28 October 2008. That plan is approved by prefectoral order of 28 February 2012, between the promise and the deed; the risk statement attached to the deed does not mention it.
In 2016 the buyers decide to build. The municipality issues them a negative planning certificate, the project lying in a very high hazard zone of the approved plan. They sue the sellers and the notaries for rescission of the sale and damages. The Montpellier Court of Appeal, on 16 November 2023, dismisses them: the 2012 order merely approved the prescribed plan without changing it, a new risk statement was unnecessary and would have given the same information; it adds that the negative certificate relied on a later order of 2014.
The decision
The third civil chamber quashed the judgment (Cass. 3e civ., 19 February 2026, no. 24-10.524, published in the Bulletin), under articles L. 125-5 and L. 562-4 of the Environment Code and L. 271-4 and L. 271-5 of the Construction and Housing Code.
It recalled the rule: “if, after the promise of sale, the plot on which the property sold is located is included in a zone covered by a prescribed or approved foreseeable natural risk prevention plan, the technical diagnosis file is supplemented, on signature of the deed of sale, by a risk statement or by an update of the existing statement, the buyer being entitled, if these provisions are not complied with, to seek rescission of the contract or ask the court for a reduction of the price”. And since “the approved foreseeable natural risk prevention plan constitutes a public-interest easement and is annexed to the local plan”, it follows that “if, after a promise of sale referring to a prescribed foreseeable natural risk prevention plan, that plan has been approved before signature of the deed, the technical diagnosis file must be supplemented by an update of the risk statement resulting from the approved plan constituting a public-interest easement”.
The Court of Appeal had found that the plan had been approved since the promise and that the risk statement attached to the deed did not mention the approval order: the buyers “had not learned, through the deed, of the updated situation of their plot with regard to the public-interest easement”. It breached those provisions. It also distorted the negative planning certificate, which did refer to the order of 28 February 2012 and not to that of 2014. Remittal to the Nîmes Court of Appeal.
What this changes for valuation
Prescribed and approved are not the same. A prescribed plan announces a study; an approved plan sets an enforceable zoning and regulation, and constitutes a public-interest easement annexed to the local plan. For a building plot, moving from one to the other can remove buildability, or make it subject to costly requirements. That is the reason for the update required at the deed: the information is not “the same”.
Two remedies, one figure. The buyer may seek rescission, with restitution of the price against restitution of the land, or a reduction of the price. In both cases the court needs the value of the land as it stood in law on the day of sale: a plot in the very high hazard zone of an approved plan, hence unbuildable for a dwelling, is valued with references of non-building land in the area, gardens, farmland, leisure plots, not with building plots. The price reduction is the gap between the price paid and that value; in case of rescission, the same gap measures the additional loss.
What the report checks before quantifying. The zoning of the approved plan at the date of sale, on the regulatory map and in the regulation; the planning certificate; the plot’s position under the local plan; the easements annexed to it. The commune pages of this site give, for each commune, the risks recorded by Géorisques and the natural disaster orders; they are a first bearing, never evidence.
For sellers and notaries. The obligation bears on the technical diagnosis file at the deed. An old promise and a deed signed several months later call for a check of the orders issued in between: approval of a plan, amendment, revision. Liability is then shared according to the documents, but the buyer’s loss is computed in the same way.
The link with the value of exposed property. Beyond bare land, an approved prevention plan weighs on the value of existing houses: required works, limits on extensions, insurability. A market-value appraisal in a covered zone describes those constraints and their effect on the comparables; it is a point to address, with its source, in any report on property in a flood zone.
What the valuer takes from it
- The approval of a prevention plan between the promise and the deed requires an update of the risk statement at the deed.
- The breach opens rescission or a price reduction, two remedies that rest on the value of the land as it stands in law at the date of sale.
- A plot in a very high hazard zone is valued with references of non-building land, not building plots.
- The report cites the map and regulation of the approved plan, the planning certificate and the easements annexed to the planning document.
- An approved plan also weighs on the value of existing houses, through required works and limits on extensions.
Further reading
The Market value page describes the assignment, its timescale and its fee. The guide I paid too much, can I challenge the price and the glossary entry valeur vénale complement this article. On the same theme: Incorrect energy certificate: a lost chance to negotiate and Wealth tax, building land and environmental constraints. The decision is available on Légifrance.
What next
A plot bought as building land that no longer is, or an incomplete risk statement?
I establish the value of the land as it stands in law at the date of sale and the gap with the price paid, with references from the area, for a claim for a price reduction or rescission.
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).
