Malka lives in Paris, a city that, like New York and San Francisco, faces growing inequality created by climbing real estate prices. So as Malka sees it, Parisians need a way to "reclaim" the city. His idea is a modular micro-city consisting of rooms that attach to scaffolding built around existing infrastructure, like barnacles clinging to a ship.He calls it the P9 Mobile-Ghetto, and has imagined them here hanging off the side of the Pont Neuf bridge in Paris.

"In a time when we are getting more and more mobile, not only regarding our phone and laptop devices, but also…the increasing number of freelancers or homeworkers, mobile-cities would totally change the uses and the morphology of the city," Malka says. In practice, this means that the idea of a third space—in which city dwellers inhabit coffee shops and parks the way others gather in their living rooms, or regard shared bicycle programs as their own bikes—extends to include a smattering of rooms or event spaces created for the public, and run by the public. The bridge can become your meditation center; an out-of-use monument could become an art gallery.

Obvious complications with zoning and historical preservationists aside, Malka says the Voluntary Ghetto is technically plausible, and would just require using scaffolding to support shipping container-sized rooms. That said, this (conceptual) new layer of infrastructure says more about urban lifestyles than it does about feats of architecture. Would Parisians (or New Yorkers, or Londoners, or any city residents) delight in finding more intimate, indoor, spaces, or would it feel like a brash paint job on a historic city? "If there is an utopia in this project," Malka says, "it's more in its social dimension than its architectural aspect.