Polluted soil in France (SIS): disclosure and soil study

What is a soil information area?

SIS were created by the loi Alur (Alur Act) of 24 March 2014 (article 173) to preserve the record of polluted sites (ministère de la Transition écologique (Ministry for Ecological Transition), page updated on 28 July 2025). Most often this is residual pollution, after the remediation of a former industrial site.

Being in an SIS does not mean that land is dangerous. According to the ministry, land classified as SIS poses no risk to the population if it is used for the purpose and under the conditions set when it was remediated. The issue arises mainly when you want to change its use, for example to build a home where an industrial activity used to be.

The procedure is set by article L125-6 of the Environment Code:

1. the State draws up draft areas on the basis of the information available to it;
2. the préfet seeks the opinion of the mayors concerned and informs the owners of the land;
3. SIS are set by the préfet, shown on plans and annexed to the PLU, to the document taking its place or to the carte communale.

Where to check: SIS, CASIAS and the planning certificate

Three tools preserve the record of pollution; the ministry states that they are all made available on the Géorisques website:

Sources: ministère de la Transition écologique; Environment Code, art. L125-6. The certificat d’urbanisme (planning certificate) shows whether the land is on a site listed in CASIAS or on a former industrial or service site known to the planning department (art. L125-6, IV). This is one more reason to apply for it before buying: see our guide on achat d’un terrain (buying a plot of land).

Sale or letting: written notice to the buyer

When land in an SIS is the subject of a contract of sale or lease, the seller or landlord must inform the buyer or tenant in writing and pass on the information made public by the State. The deed of sale or lease records that this formality has been completed (Environment Code, art. L125-7).

Do not confuse it with the risk statement. SIS are not among the eight areas that require an état des risques (risk statement) (service-public.gouv.fr, checked on 28 September 2026; Environment Code, art. R125-23). Soil information is a separate obligation, which is in addition to the risk statement without replacing it (art. L125-7). The CCH (Construction and Housing Code) lists it among the information provided on a sale or letting (art. L126-23). For other risks, see our guide on the état des risques (ERP) (risk statement).

Former industrial site. If an installation subject to authorisation or registration was operated on the land, the seller must also inform the buyer of this in writing, together with any significant dangers or drawbacks they know of (art. L514-20).

Building on land in an SIS: the soil study

Any building or lotissement (housing development) project planned in an SIS is subject to a soil study, which sets out the pollution management measures ensuring that the future use is compatible with the state of the soil (Environment Code, art. L556-2).

• For a project requiring a permis de construire (building permit) or permis d’aménager (development permit), the maître d’ouvrage (client commissioning the works) attaches to the application a certificate guaranteeing that this study has been carried out and taken into account in the design of the project.
• This certificate is issued by a consultancy accredited in the field of polluted sites and soils, or equivalent. The ministry calls it ATTES-ALUR.

The same logic applies to a change of use of land that housed a classified installation that has been shut down and remediated: the maître d’ouvrage initiating the new use defines and implements pollution management measures (art. L556-1).

The buyer’s remedies

If written notice was not given and established pollution makes the land unfit for the purpose stated in the contract (or, failing that, for the intended use), the buyer or tenant may, within 2 years of discovering the pollution (Environment Code, art. L125-7):

The same 2-year period and the same options (rescission, refund of part of the price, remediation) apply to the buyer of land where a classified installation was operated without their being informed (art. L514-20). For defects not covered by these texts, see our guide on vices cachés (hidden defects).

Which professional to consult

The notaire (notary) checks that the deed records the written notice of the SIS and identifies the public-interest easements affecting the land. The géomètre-expert (chartered land surveyor) places the plot precisely in relation to the boundary of the area. The agent immobilier (estate agent) can gather the information published by the State as soon as the property is put up for sale. The diagnostiqueur (property surveyor) carries out the other surveys in the sale file.