Erected in the 1960s, the 4000 was meant as a utopia, an experiment in social engineering that would rationalize the lives of the immigrant workers it would house.
The theory of the day, drawing on the architectural philosophy of Le Corbusier, held that residential areas ought to remain separate from roads and the workplace, and so the cluster was built as a sort of island; residents trudged across a muddy field to reach the adjacent train station. Each airy apartment was equipped with a bathroom, a relative rarity in Paris at the time. The complex was deemed revolutionary.
A model of the 4000 was exhibited at the Grand Palais in 1961.
And yet, while the particular philosophy underlying the 4000 has been disavowed, few French officials have jettisoned a belief in the primacy of architecture in shaping social outcomes, said Marie-Christine Vatov, the editor in chief at Innovapresse, a media group specializing in architecture and urban planning.
“Mixing” and “openness” have replaced “separation” and “uniformity” as the watchwords of the day. But the central lesson of the past decades, Ms. Vatov said, has been the error of such faith in the power of architecture.