Habitable surface (Boutin)
The habitable surface under the Boutin Act is the floor area of a dwelling after deducting walls, partitions, stair treads and stairwells, ducts, door and window recesses, and all areas with a ceiling height below 1.80 m. It is mandatory for unfurnished residential lease agreements.
Key points
- The Boutin Act (2009) requires the habitable surface area to be stated in every unfurnished residential lease.
- It differs from the Carrez surface, which applies to condominium sales and excludes areas below 1.80 m but includes enclosed annexes (non-habitable cellars excluded).
- An error of more than 5% on the Carrez surface stated in a sale deed entitles the buyer to a proportional price reduction.
- An error on the Boutin surface in a lease does not give rise to a price reduction but may expose the landlord to liability.
- Terraces, balconies, cellars, and parking spaces are never included in the Boutin habitable surface.
Frequently asked questions
What is the practical difference between the Boutin surface and the Carrez surface?
Both methods exclude areas with a ceiling height below 1.80 m, but they apply in different contexts: the Boutin surface applies to rental leases (unfurnished primary residences); the Carrez surface applies to condominium sales. In practice, the two measurements are often close but may differ slightly depending on how wall deductions are calculated.
Why does the habitable surface affect the mortgage loan amount?
Banks and property appraisers use the habitable surface to compute the price per square meter and estimate the market value. If the actual area is smaller than stated in the preliminary agreement, the appraisal value — and thus the financeable amount — may be reduced. The broker must ensure that the surface area in the file matches the actual measurement.
How can I be compensated if the Carrez surface was wrong when I bought?
The buyer has one year from the signing of the authentic deed to pursue a price reduction if the actual area is more than 5% less than the stated surface. The claim may be pursued amicably or in court, supported by a contradictory measurement carried out by a licensed surveyor or certified diagnostician.
In practice
A buyer commissions an independent Carrez measurement on an apartment advertised at 68 sq m. The measurement reveals 63.5 sq m — a 6.6% discrepancy. The buyer invokes the price-reduction clause within the one-year deadline and obtains a €4,500 discount, which the bank factors in when recalculating the loan amount.
Official sources
- Minimum height and area of a dwelling to rent · Service-Public.gouv.fr
- Sale agreement and loan condition precedent · Service-Public.gouv.fr
- Housing and financing information · ANIL