The then-disease-plagued Marais (which was also historically its Jewish quarter) would be replaced by a gridded phalanx of 18 cruciform office towers over several square miles. The towers would sit in a multi-tiered park. One level was an immense amount of green space. Another level was for transportation. An airport was even included in the designs. Low-rise residential and government buildings appear in the northern corners and along the river.

Where before the streets of Paris were choking on pollution and disease, Corbusier’s design created an ordered urban landscape that separated out the different facets of life and gave them space and order.

The Plan Voisin grew out of Le Corbusier's ideas about the Ville Contemporaine, the modern city, which he had made public in 1922. It represented Corbusier's dream of a new age industrial metropolis.

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“I think that the Plan Voisin is one of the most misunderstood projects in history,” Nicholas Fox Weber, author of the seminal biography Le Corbusier: A Life tells me over the phone. “Corbusier gets a bum rap, and people like to describe him as the man who was willing to destroy Paris, or to raze all of Paris, or take down everything that was in the Marais.” Instead [says Weber,] we should keep in mind that this was a hypothetical “and should be treated as such.”

“The visitors to the Expositions des Arts Decoratifs where it was exhibited were impressed,” architectural historian Jean-Louis Cohen wrote in an email to me. “Some of them even commissioned buildings from Le Corbusier.” In fact, says Cohen, “there were many articles in the press, underlining the “American” aspect of the plan, admiring its ambition, and seeing in it the ineluctable destiny of Paris.”