It's a town where retired people take refuge to live in safety, far from a society that frightens them. At the entrance to the port, under the summer sky, yachts maintain the image of a perfect world, where everything is carefree and light. But in winter, when the beaches have emptied, all that's left is the decor, a dehumanized ghost town... Back in the 60s, when the architect conceived and designed it, this town was supposed to be paradise, a carefree world where everyone would be free from the constraints of industrialized civilization. By surveying the city today, the filmmaker attempts to discover the utopia that history has swallowed up. Inspired by the story of a seaside resort created ex-nihilo on the Languedoc coast, “La Cité du soleil” recounts the mad project of an architect who dreamed of reconciling utopia and mass tourism, dreams and consumer society.