After visiting Kyoto’s Katsura Imperial Villa in 1940, Charlotte Perriand developed an obsession: the shelves.“[They were] arranged on the walls, in the form of a cloud,” the French designer wrote in her journal. “A free form that gives rhythm to space and enhances the objects it supports.”

Perriand at the Expo Synthèse des Arts Tokyo in 1955.

Nearly a decade later, she unveiled Nuage (French for “cloud”), a modular bookshelf that could be rearranged in various configurations, thanks to sliding panels, trays, and shelves. Perriand marveled at the way simple components could create entire walls or pieces of furniture. The first renditions were made of wood—due to war rationing it was the only material available—but by the time the series officially debuted in 1956, the shelves included aluminum.

A Nuage adds a colorful pop to the midcentury French decor of dealer Miquel Alzueta’s Barcelona home.

For a design rooted in serenity, Nuage has had a turbulent history. When originals—produced for about 15 years by Galerie Steph Simon—emerged on the secondary market in the 1990s, a misconception followed: that the shelf had been codesigned by French master Jean Prouvé , whose factory also produced his friend Perriand’s furniture.

A 1957 Nuage.

The credit issue caused problems, for scholarship and for pocketbooks. “The price of Prouvé’s furniture was higher than the price of Perriand’s,” explains Perriand expert (and son-in-law) Jacques Barsac. He and his wife, Pernette, sorted things out in court by 2012.

Regardless of attribution, the shelf’s cult status led to another issue: fakes. “Nine out of ten you see are contemporary fabrications,” estimates Michael Boyd, a midcentury connoisseur who has negotiated refunds for fellow collectors who were sold fakes at auction. For buyers who don’t want to risk it (an authentic Nuage goes for upwards of $100,000 at auction), Cassina produces authorized versions starting at $8,855. cassinaom