23/06/2026
The ‘Maine-Montparnasse project’, carried out between 1969 and 1973, was one of those fairly destructive urban renewal schemes that shaped post-war Paris. It involved the demolition of the former train station from 1852, as well as around 4,400 homes, to make way for a modernist district.
A curious feature of this redevelopment is ‘Sector 4’ – the complex comprising the Paris-Montparnasse railway station itself and a 54,000 sqm office building literally standing on top of it. Its distinctive curtain wall façade of black granite and aluminium, shaped like a folding screen, used to face the station square. Originally built for the French railway company SNCF, the office building was used by CNP Insurance in the decades that followed.
In 2025, the original façade of the CNP building was removed as part of a refurbishment project. We were given the opportunity to recover the stone panels – and what a material! The black granite (actually gabbro, to use the geological term) is in excellent condition after more than 50 years of service. The perfectly square slabs of 115 x 115 cm were attached using a surprisingly simple system: no mortar, no glue, no bolts or anchors; they were simply held in place by aluminium profiles on all 4 edges. As a result, they came out intact and clean from the dismantling.
The exposed side is polished and is therefore dark and shiny, whilst the reverse side has a sanded finish and a light grey tone. We believe that, for their next use, the polished side would make excellent table tops, and the reverse side would be perfect for use as a flooring material, as it is non-slip.
More information:
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Archive drawing: Archives Historiques de la S.N.C.F
Archive picture and plan: Service de Politique Urbaine, "Maine-Montparnasse préfiguration d’un “pôle” de développement urbain?", 1970
