Quarries and subsurface of Paris’s 16th arrondissement
Moderate risk Paris 75016
The 16th arrondissement is the only one in our scope located on the right bank. Its Chaillot network covers around 39 hectares and 7 km of galleries (Chaillot quarry, rue de Bassano quarry). Less extensive than the Grand Réseau Sud, it nevertheless presents a localised risk, particularly around Trocadéro, Passy and la Muette. The coarse limestone outcrops there and was quarried for building stone.
What the public data say about the 16th
| Underground network | Réseau de Chaillot (rive droite) |
|---|---|
| Mined rock | Lutetian coarse limestone |
| Undermined area | 39 undermined hectares. |
| Galleries | ~7 km of galleries. |
| Selected risk level | Moderate |
| Confidence in the classification | high |
| Nature of the ground | Chaillot limestone plateau + Seine banks |
| Foundation issue | Load-bearing limestone ground on the plateau; loose alluvium to be checked near the Auteuil riverbanks. A G1/G2 geotechnical study is recommended before construction. |
Sensitive areas of the 16th
- Chaillot quarry, rue de Bassano quarry
- Trocadéro, Passy, Muette areas
- The only limestone arrondissement on the right bank
Ground, fill and clay shrink-swell
The 16th arrondissement lies on the Chaillot limestone plateau (see quarries section), with alluvial deposits along the Seine banks (Auteuil, Maison de la Radio).
Load-bearing limestone ground on the plateau; loose alluvium to be checked near the Auteuil riverbanks. A G1/G2 geotechnical study is recommended before construction.
Unlike almost all French municipalities, inner Paris has no official mapping of the clay shrink-swell hazard (RGA). The BRGM explains this explicitly: the Paris subsoil is largely made up of reworked and artificial materials (backfill, infilled former quarries), which does not correspond to the standard methodology for this mapping — centred on detached houses, which are in the minority in Paris. This does not mean that there is no risk of differential settlement, but that no official area-by-area study exists for the capital: a ground investigation remains the only reliable way to assess a specific plot before purchase or construction.
Steps to take in the 16th before a purchase or works
Moderate but present risk: consultation with the IGC (Paris quarry inspectorate) and a subsurface check are recommended before any construction project, especially in the Chaillot/Passy area.
- IGC (Paris quarry inspectorate) information sheet — the authoritative source on the condition of the parcel’s subsoil: €10, issued within 8 days, via the City of Paris online service.
- Statutory risk statement (ERP) — mandatory for sale and letting, generated from Errial; note, it does not return cavity data in Paris.
- geotechnical survey — G1 mission before purchasing a building plot, G2 AVP before a construction or underpinning project.
- Referral to the IGC (Paris quarry inspectorate) for planning — prefectoral orders require it to be consulted for any planning permission in a quarry-risk area.
Frequently asked questions
Are there underground quarries beneath Paris’s 16th arrondissement?
Yes. The 16th arrondissement is recorded in the public data of the IGC (Paris quarry inspectorate) as an area affected by the « Réseau de Chaillot (rive droite) » network, in Lutetian coarse limestone. The risk level selected is « Moderate », with high confidence in the classification of the area. Right-bank network: Chaillot quarry and the rue de Bassano quarry. The only right-bank limestone arrondissement.
How can I find out whether my exact address in the 16th is in an undermined area?
Quarry zoning must be read at plot level rather than arrondissement level. There are two options: the official information sheet from the IGC (Paris quarry inspectorate), at €10 and issued within 8 days, which is the legally binding source; and Sous-sol Paris’s instant pre-assessment, at €15, which matches your address against public data and immediately provides you with a readable report, including the steps to take. This pre-assessment is for information only and does not replace the IGC information sheet, the statutory risk statement (ERP), or a geotechnical study.
Why do cavity data for the 16th not appear on Géorisques?
Because for départements 75, 78, 91, 92, 93, 94 and 95, cavity data are not published on the Géorisques portal: they can be consulted with the IGC (Paris quarry inspectorate) for Paris and the inner suburbs, or with the relevant interdepartmental service. This is why a standard statutory risk statement (ERP) remains silent on Paris quarries and gypsum.
Is the 16th’s quarry risk covered by insurance?
Disorders linked to former quarries do not fall under the « natural disaster » scheme. In the event of collapse, infill works, estimated at 40 000 to 200 000 €, remain the responsibility of the owners. This is what makes checking before purchase essential.
Other arrondissements
- Subsoil of the 15th arrondissement
- Subsurface of the 17th arrondissement
- Subsoil of the 14th arrondissement
- Subsoil of the 18th arrondissement
- Subsurface of the 5th arrondissement
- Subsoil of the 6th arrondissement
- Subsoil of the 7th arrondissement
- Subsoil of the 12th arrondissement
- Subsurface of the 13th arrondissement
- See the 20 arrondissements
Sources
- City of Paris — Everything you need to know about the subsurfaces
- Institut Paris Région — Underground risk study (quarries)
- Wikipedia — Underground quarries of Paris
- Wikipedia — Paris, Geology section
- BRGM — Why is there no map of the clay shrink-swell hazard for Paris?
- Géorisques — Clay shrink-swell, 2026 version (data)
- Géorisques — Underground cavities (data)
- City of Paris — the IGC (Paris quarry inspectorate) location
- City of Paris — Known areas of former quarries (IGC)
Page updated on 11 September 2026.