Carrières des Brillants

Carrières des Brillants is a network of former underground chalk quarries carved into the Brillants hill, straddling the border of three Hauts-de-Seine communes — Issy-les-Moulineaux, Meudon and Clamart — just west of Paris. It ranks among the best-preserved remnants of the raw-material industry that once supplied the French capital, and today it is also the focus of a heated heritage-protection dispute.

What kind of quarry is this?

Unlike the famous limestone quarries beneath the Left Bank of Paris, the Brillants site was worked for chalk, a soft white rock long marketed as "blanc de Meudon" (Meudon white). The main gallery network is also known as the Arnaudet quarry, named after rue du Docteur-Arnaudet in Meudon, where one of the entrances is located. Beneath the hill, several levels of tunnels and chambers are held up by massive chalk pillars left in place during extraction.

How long was it worked, and what was the chalk used for?

Large-scale extraction at this particular site began in 1872 and continued for decades. Soft Meudon chalk had a surprisingly wide range of industrial uses: it went into putty and fillers, served as a pigment base for paint, was used for polishing silver, for casting sculptors' moulds, and for producing the classic white chalk used on school blackboards. Steady demand for these applications kept the quarry active well into the following century.

What is actually underground?

The workings beneath Brillants hill total roughly eight kilometres of galleries. Passages range from 3 to 15 metres in height and 3 to 4 metres in width, spread across four or five levels, three of which remain accessible today. The chambers are braced by wide chalk pillars, a construction method typical of quarries of this kind. The site is part of a much larger system of former quarries running beneath several Hauts-de-Seine communes — Issy-les-Moulineaux, Sèvres, Meudon and Clamart — covering dozens of hectares underground in total, a regional counterpart to the better-known limestone quarry network under the Paris Left Bank, though cut through a different rock.

Why is it protected, and what is its link to Rodin?

The Arnaudet quarry was listed as a historic monument by decree on 7 March 1986, recognised for its scientific and artistic value. The hill itself is sometimes informally called "Rodin's hill": sculptor Auguste Rodin spent his final years nearby at his estate, the Villa des Brillants, next to the quarry — a detail that ties the site to art history, even though the villa and the underground quarry are distinct places.

The current dispute over backfilling

In recent years, the future of Carrières des Brillants has become contentious. Local authorities obtained approval to partially backfill the galleries with earth excavated during construction of the Grand Paris Express metro lines. The plan was challenged by scientists, cave explorers, residents, and heritage and environmental groups, who feared the irreversible loss of part of the quarry system. In October 2020, the administrative court of Cergy-Pontoise annulled the work authorisation, but in July 2021 the town council and the environment ministry won on appeal. Backfilling work began in June 2022, even as a further cassation appeal remained pending.

Frequently asked questions

Can visitors go inside Carrières des Brillants? No, it is not a general tourist attraction. As a protected heritage site, access is restricted for safety and conservation reasons.

How is this different from the Paris Catacombs? The Paris Catacombs beneath the Left Bank were cut from limestone, while Brillants is a chalk quarry — a different rock and a different extraction history, even though both belong to the wider tradition of underground quarrying in the Paris region.

Why is the site in the news? Because part of its galleries are being permanently filled with earth from metro construction, which opponents say threatens a unique piece of regional industrial and scientific heritage.

Where does the name "Brillants" come from? It comes from the hill on which the quarry lies — the same hill where sculptor Auguste Rodin kept his estate, the Villa des Brillants.