Sous-sol Paris

Quarry risk pre-assessment for your address

Public data from the IGC (Paris quarry inspectorate)

Is your home above a former quarry in Paris?

Enter your address for an instant pre-assessment of ground movement risk (cavities, sinkholes (fontis), subsidence). Paris has more than 835 hectares of former underground quarries (limestone + gypsum) spread across 12 arrondissements.

Enter a street number and street name in Paris, then choose a suggestion from the list.

Interactive map of undermined zones and recent collapses. Data: City of Paris / IGC, Institut Paris Région, BRGM.

Product preview

What does the detailed report look like?

Before ordering, take a look at a full sample generated for a fictitious address in the 14e arrondissement (high-risk zone). The report you receive for your own address follows exactly the same structure, with the data specific to your area.

PARIS UNDERGROUND PRE-ASSESSMENT
Pre-assessment report
Address: 42 rue Daguerre, 75014 Paris
High risk
1. Executive summary
2. Characteristics of the area
3. Sensitive settings and areas

What every report contains

  • Executive summary : clear verdict, type of risk, confidence level
  • Characteristics of the area : quarry network, rock type, undermined area, galleries
  • Sensitive settings in the neighbourhood
  • Documented events in the area (sinkholes (fontis), historic collapses)
  • What this means for buying, building work and insurance
  • Practical next steps : IGC, ERP risk statement, geotechnical survey (with costs and timescales)
  • Warning signs to look out for on site
  • Specific recommendations for your area
  • Limitations & uncertainties (transparent about what the report does not claim)

5-page PDF • generated live • identical to the real report

By arrondissement

Quarry risk in each Paris arrondissement

Methodology

Where does the data come from?

This service is a plain-language summary of public data : City of Paris / Inspection Générale des Carrières (the IGC, Paris quarry inspectorate), Institut Paris Région, BRGM / Géorisques, DRIEAT Île-de-France and press sources. The zones shown are area-level indicators, not the exact geometry of the quarries — the precise plans can only be consulted at the IGC.

This pre-assessment does not replace a consultation with theIGC, a statutory risk statement (ERP / Errial), a geotechnical survey, or the involvement of a property surveyor or a notary. Event coordinates are approximate (street/neighbourhood accuracy).

Frequently asked questions

Everything you need to know about quarry risk in Paris

Answers to the questions most often asked by Paris property owners, buyers and property professionals.

How do I know if my house is above a quarry in Paris?

Enter your address in our pre-assessment tool at the top of the page. We instantly cross-reference your location with the public data of theInspection Générale des Carrières (the IGC, Paris quarry inspectorate) and of Géorisques to identify whether you are in a risk zone: former limestone quarries, gypsum pockets or dissolution zones.

The free pre-assessment tells you your risk level immediately. The detailed 15 € report adds the exact nature of the underground, the history of known incidents within a 200 m radius and expert recommendations.

Which Paris arrondissements are affected by quarry risk?

Paris has more than 835 hectares of former underground quarries spread across 12 arrondissements:

  • Limestone quarries (Left Bank): 5e, 6e, 13e, 14e, 15e, 16e
  • Gypsum quarries (Right Bank / east): 10e, 12e, 18e, 19e, 20e
  • Mixed zones or zones of limited sensitivity : 4e, 11e, 17e

The central arrondissements (1st, 2e, 3e, 7e, 8e, 9e) are largely unaffected, but every address should be checked individually.

What is the difference between a quarry and a sinkhole (fontis)?

A quarry is a man-made underground cavity dug to extract stone (limestone or gypsum). Paris has hundreds of kilometres of them, dug from the Middle Ages to the 19e century.

A sinkhole (fontis) is the gradual collapse of a quarry roof. The void migrates towards the surface year after year and can eventually cause a crater to appear suddenly at ground level (a car swallowed up, a building façade cracking, a road subsiding).

What does the detailed 15 € report contain?

The 5-page PDF report contains:

  • The risk analysis for your exact address (not just the neighbourhood)
  • The nature of the underground (limestone, gypsum, backfill, alluvium)
  • The estimated depth of the cavities and their age
  • L'history of ground movements known within a 200 m radius
  • The expert recommendations (IGC, geotechnical engineer, notary)
  • An annotated map of your area

The report is delivered instantly by email after payment and can be downloaded as a PDF.

Does this report replace the ERP risk statement or a mandatory diagnosis?

No. Our report is an informative pre-assessment. It in no way replaces:

  • L'the État des Risques et Pollutions (ERP risk statement) required when selling — available free of charge at Errial.georisques.gouv.fr
  • The official consultation of theInspection Générale des Carrières
  • A geotechnical survey by a specialist engineering consultancy
  • The expert opinion of a notary or of a property surveyor

Our added value: a first clear, immediate and readable verdict before you commit to heavier procedures.

Can I have several addresses checked (estate agency, managing agent, notary)?

Yes. We offer two packages for property professionals:

  • Starter Pack — 49 € : 10 detailed reports to use whenever you like, with no expiry date.
  • Pro subscription — 59 €/month : unlimited reports, a tracking dashboard and export of the addresses you have checked.

See thepro area for details, or theoffer for notaries & estate agents.

How deep are the Paris quarries?

It depends on the type of quarry and on the topography of the neighbourhood:

  • Limestone quarries : generally between 10 and 40 m below the surface (sometimes less in the 5e and the 14e).
  • Gypsum quarries : rather between 15 and 30 m, with some shallow zones towards Ménilmontant and Belleville.

The closer the quarry is to the surface, the higher the risk of a sinkhole (fontis) if anything goes wrong.

What should I do if my address is in a risk zone?

Don’t panic — being in a risk zone does not mean that a collapse is going to happen. Here is the right approach:

  1. Consult the IGC to obtain the precise plan of the cavities beneath your plot (free of charge, by appointment).
  2. Check the date of construction : buildings put up after 1975 will normally have been the subject of soil surveys.
  3. Look into the building’s history : cracks, settlement, previous structural issues.
  4. If you are buying, ask your notary for a geotechnical survey (G1/G2 studies).
  5. Home insurance : check that « ground movement » cover is included.

Another question? contact@sous-sol-paris.com