Overview of the Court Ruling
Under the French law of 10 July 1965 (art. 46), a buyer can claim a proportional price reduction when the actual surface area falls more than 5% below the area stated in the deed — and in a VEFA, the Carrez law only applies in full if the contract expressly refers to it (Cour de cassation, Third Civil Chamber, 18 March 2021, appeal no. 19-24.994). Previously (Cour de cassation) confirmed that a buyer under a VEFA contract (off-plan sale, « vente en l’état futur d’achèvement ») can obtain a price reduction if the Carrez surface area (French law of 10 July 1965) is more than 5% smaller than the figure stated in the sale deed. In this case, a buyer had purchased an off-plan flat with a stated Carrez surface area of 65 m². After handover, a land surveying expert measured 58 m² — a 10.8% shortfall. The developer refused to reduce the price, arguing that the measurement wrongly included walls and partitions. The Court of Appeal had sided with the developer. The Cour de cassation overturned that ruling, holding that the Carrez surface must be calculated according to established professional standards (Decree no. 97-532), excluding walls, partitions, stairs, etc., and that the land surveying expert was qualified to determine the exact surface area.
Technical Analysis
The Carrez surface area (law of 10 July 1965) is the floor area of enclosed, covered rooms, after deducting the space taken up by walls, partitions, stairs and door recesses. It excludes unconverted attics, cellars, garages, etc. Measurement must be carried out by a professional (land surveying expert, architect, diagnostician) in accordance with standard NF P 04-501. The land surveying expert uses a laser rangefinder and CAD software to calculate the surface area with precision (tolerance of 0.1 m²). In a VEFA purchase, the buyer has one year from the date the deed is signed before a notary to claim a proportional price reduction if the shortfall exceeds 5%.
Case Study: A Cassini Expertise Intervention
Mr. Martin buys an off-plan flat in Paris, with a stated Carrez surface area of 55 m². At handover, he measures it himself and finds only 50 m². He instructs Cassini Expertise to carry out an official measurement.
Findings: The Cassini Expertise land surveying expert visits the property and carries out a 3D laser survey. They find that the developer had included in the Carrez surface the thickness of the interior walls (0.20 m) and part of the uncovered balcony.
Measurements and analysis: The expert applies established professional standards: deducting walls, partitions, and uncovered areas. This produces a Carrez surface area of 49.8 m² — a 9.5% shortfall.
Expert report: The expert drafts a detailed report with scaled plans, calculations, and photographs, concluding that the actual surface area is more than 5% smaller than stated.
Court outcome: On the strength of this report, Mr. Martin sues the developer for a price reduction. The court orders the developer to refund 9.5% of the sale price (€19,000 out of €200,000). The Court of Appeal upholds the ruling, and the Cour de cassation dismisses the developer’s appeal.
Key Takeaways
- For VEFA buyers: have the Carrez surface area measured by an independent expert as soon as you take handover, and act within one year of signing the deed before a notary.
- For developers: strictly follow the rules for calculating the Carrez surface area, or risk having to reduce the price.
- The land surveying expert is the most qualified professional for this type of measurement.
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Frequently Asked Questions
What is the Carrez surface area?
It is the floor area of enclosed, covered rooms, after deducting walls, partitions, stairs, etc. It is a mandatory disclosure in the sale deed for co-owned lots.
What is the deadline to act over an incorrect Carrez surface area?
The buyer has one year from the date the deed is signed before a notary to claim a price reduction if the shortfall exceeds 5%.
How does an expert carry out a Carrez measurement?
The expert uses a laser rangefinder, measures each room, deducts the areas that do not count (walls, partitions), and produces a scaled plan with the surface area calculation.
What if the developer disputes the measurement?
It is advisable to call in a judicial expert to settle the matter. The expert assessment can be ordered under an expedited (référé) procedure.
📅 Updated on 20/08/2026 — By Cassini Expertise, independent building expert covering the Alpes-Maritimes (06) & Var (83). Free quote: 04 22 46 06 04.
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