A risk map helps you ask informed questions. It does not replace a formal risk statement, prevention-plan rules or a ground investigation for your project.
Prepared by Carteparcelle · OPL Consulting Oy · Sources checked on
Identify the scope of each finding
A parcel page may combine parcel-level calculations with categories assigned to the commune. Read the label and source before comparing results. “Not recorded” describes a limit in the available data, not a guarantee that a risk is absent.
For clay shrink-swell, BRGM explains that the exposure map relies on geological knowledge at a scale that cannot describe the exact ground at every point. A geotechnical investigation can provide local information that cannot be inferred from the map.
BRGM / Géorisques — Retrait-gonflement des argiles et limites de la carte
Why two layers can differ
Fictional example: a prescription in an older PLU mentions low hazard while a national map shows medium exposure. First compare the publisher, date, phenomenon and purpose of the documents. Do not simply choose the more favourable result or add percentages from different layers.
The national clay-exposure map has been updated. Géorisques explains the new map and its application to certain contracts concluded from 1 July 2026. For a current transaction, open the official source instead of assuming that a PLU’s date reflects the latest risk knowledge.
BRGM / Géorisques — Retrait-gonflement des argiles et limites de la carte
Prepare the formal risk statement
For affected sales and rentals, the état des risques is a separate document from our parcel page. Service Public says it must be less than six months old and updated if its information is no longer accurate at signing. Use the official guidance to determine the obligations for your situation.
ERRIAL locates a property by address or cadastral reference and prefills a risk statement. The owner must check and complete it, including information they know about the property. Downloading a prefilled document does not remove that responsibility.
Service Public — Diagnostic immobilier : état des risques · Géorisques — Préparer et compléter un état des risques avec ERRIAL
Keep a record and ask a specific question
Keep the parcel reference, consultation dates and downloaded documents. If a prevention-plan perimeter appears, also read its regulations: the outline alone does not describe every consequence for a proposal.
For a planning question, take these documents to the planning department. For questions about the ground or a building, consult the relevant professional. Carteparcelle helps prepare the discussion; it does not certify that land is safe or free from previous damage.
These guides provide general information. Before making a decision about a property, confirm the relevant details with the responsible authority or professional.
Official sources
The links below lead to official sources in French.