How is the living surface calculated in France?

CARREZ LAW: HOW IS THE SURFACE CALCULATED?

Enacted on December 18, 1996, and named after French politician Gilles Carrez, this legislation ensures transparency in real estate transactions by requiring accurate property measurements.

The Carrez Law living surface calculation allows for the definition of the living and private area of a property within a condominium, whether it’s a vertical building (apartment complex) or a horizontal development (housing estate).

The Carrez Law surface is determined by considering the enclosed and covered space that is exclusively for private use, as opposed to common areas. Please note that the Carrez measurement must be attached to the promise and deed of sale.​

CARREZ LAW: CALCULATION OF THE LIVING AREAS

The surface defined through the Carrez Law calculation corresponds to the actual living area of a property. To measure it correctly, certain elements need to be subtracted:

• Walls and partitions;
• Stairs and stairwells;
• Door and window recesses;
• Shafts;
• Balconies and terraces;
• Annexes such as cellars or garages.

Only areas with a ceiling height of at least 1.80 meters are taken into account. Rooms or fractions of less than 8 square meters are only included in the calculation if they are integrated into the “living unit.” For example, an independent small maid’s room would not be counted. However, if they are indeed enclosed and covered spaces with a ceiling height of over 1.80 meters, the following areas are measured:

• Basement (excluding cellars and parking);
• Attics and loft spaces, even if not converted;
• Storage rooms and sheds;
• Or even a conservatory.

WHO CAN CALCULATE A CARREZ LAW LIVING SURFACE?

The Carrez Law does not mandate that you must hire a professional to perform the measurement. You can do it yourself. To calculate the Carrez surface, you simply need to measure each room from the inside of the walls and partitions. For instance, if you have a room that measures 4 m x 4 m, it will be counted as 16 sqm.

However, be aware of potential pitfalls! Mansard roofs, removable conservatories, and closets can present real challenges. Additionally, if you make a mistake in the calculation, you could be held liable. Thus, it may be prudent to seek the services of a certified diagnostician.

Professional Carrez diagnostician costs range from €85 to €150 depending on the property type (studio, duplex, converted attic, etc.) and location. In Paris, diagnostic costs are typically higher, with essential diagnostic packs averaging €700-800 in 2024. Thus, it may be prudent to seek the services of a certified diagnostician to avoid costly errors.

CALCULATION OF CARREZ LAW SURFACE: OBLIGATIONS AND PENALTIES

The Carrez Law surface calculation must be attached to the promise of sale. If this is not the case, and if the deed of sale does not mention the private surface of the property, the buyer has one month from the signature to request the nullity of the sale. However, this omission is extremely rare, as the notary ensures compliance.

More commonly, DIY Carrez surface calculations may be somewhat exaggerated. If the surface area indicated in the promise and deed of sale exceeds the property’s actual area by more than 5%, the buyer has one year to request a price revision. The refund calculation is directly related to the percentage of the additional declared surface. Moreover, the buyer may also obtain a refund of the notary fees, which are correlated to the size of the property.

To avoid this unpleasant surprise, we strongly advise you to seek the assistance of a professional when measuring the Carrez Law surface. Since the July 2024 reform strengthening diagnostician qualifications, average diagnostic prices have increased by 10-15%, with greater increases anticipated through 2026. However, investing €100-150 in a professional measurement can save you from disputes worth thousands of euros in price adjustments.​