Quarries and subsoil of Paris’s 12th arrondissement
High risk Paris 75012
The 12th arrondissement (Bercy, Bel-Air, Picpus, Quinze-Vingts) is explicitly listed by the IGC (Paris quarry inspectorate) among the Paris arrondissements with Lutetian coarse limestone, alongside the 5th, 6th, 13th, 14th, 15th and 16th. It is part of the Grand Réseau Sud. The Bercy and Picpus sectors, close to the southern network, are particularly affected by the risk of underground cavities.
What public data say about the 12th
| Underground network | Grand Réseau Sud (GRS) |
|---|---|
| Mined rock | Lutetian coarse limestone |
| Undermined area | Part of the ~508 ha of the Grand Réseau Sud. |
| Galleries | Included in the GRS’s ~200 km of galleries. |
| Selected risk level | High |
| Confidence in the classification | high |
| Nature of the ground | Limestone plateau (GRS) + Bercy alluvial plain |
| Foundation issue | Load-bearing limestone ground on the plateau, with loose alluvium and made ground near the Seine (Bercy), which may require special foundations. A G1 then G2 geotechnical study is recommended, particularly near the riverbanks. |
Sensitive areas of the 12th
- Bercy, Bel-Air, Picpus, Quinze-Vingts sectors
- Officially listed by the IGC (Paris quarry inspectorate) among Paris’s Lutetian coarse limestone arrondissements
Ground, fill and clay shrink-swell
The 12th arrondissement combines the Lutetian coarse limestone of the Grand Réseau Sud (see quarry section) and an alluvial plain along the Seine, in the Bercy / Gare de Lyon area, where backfill and modern alluvium are common.
Load-bearing limestone ground on the plateau, with loose alluvium and made ground near the Seine (Bercy), which may require special foundations. A G1 then G2 geotechnical study is recommended, particularly near the riverbanks.
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.
Your steps in the 12th before a purchase or works
High risk: IGC (Paris quarry inspectorate) consultation and a G1 geotechnical study are recommended before purchase or works, especially towards Bercy and Picpus.
- 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 12th arrondissement?
Yes. The 12th arrondissement is listed in public data from the IGC (Paris quarry inspectorate) as an area concerned by the “Grand Réseau Sud (GRS)” network, in rock of the Lutetian coarse limestone type. The selected risk level is “High”, with high confidence in the area’s classification. The 12th is explicitly included in the IGC’s official report among Paris’s Lutetian coarse limestone arrondissements (5th,6th,12th,13th,14th,15th,16th). Bercy / Bel-Air / Picpus area.
How can I tell whether my precise address in the 12th 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 does cavity data for the 12th 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 12th’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 11th arrondissement
- Subsurface of the 13th arrondissement
- Subsoil of the 10th arrondissement
- Subsoil of the 14th arrondissement
- Subsurface of the 5th arrondissement
- Subsoil of the 6th arrondissement
- Subsoil of the 7th arrondissement
- See the 20 arrondissements
Sources
- City of Paris — Everything you need to know about the subsurfaces
- APUR — Profile of the 12th arrondissement
- 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.