The Fondation Louis Vuitton (FLV), designed by Frank Gehry, may appear transparent, but it is a building that doesn’t easily give up its secrets. Encountering it for the first time—huge and billowing, as if the vast, curving glass sails that wrap the exterior are tilting into the wind—is amazing and a little confounding. Without a surrounding cityscape against which to gauge the scale of this surprise of a building, it looms above the leafy treetops of the Bois de Boulogne in western Paris as if it were a garden folly made for giants.

But you can’t put paintings under glass, so the building is actually composed of two discrete parts. The multilevel 126,000-square-foot museum, with a concrete-and-steel structure, is largely clad in 19,000 fiber-reinforced highperformance concrete panels (its white, irregular jutting and curving shapes have been dubbed “the icebergs”). Surrounding it is “an ephemeral dress,” as Gehry calls it, open to the air and composed of 12 large floating translucent glass sails, attached to the structure via an elaborate web of steel and wood members. Arnault fell in love with Gehry’s first design in 2006, and in the Beaux Arts tradition of the esquisse—a preliminary drawing that embodies the essence of the idea—it remained the basis of what was eventually created. This is not how the architect usually works; he and his team tend to develop a design over time, building model after model to test ideas. “Every time we varied from the first model,” says Gehry, “Bernard would say, ‘But, Frank, I love that one.’ Not that it was pushing me to do something I wasn’t happy with.”

Almost every news article about the fashion magnate terms him “the richest man in France,” and, with the FLV, he commissioned an extraordinary piece of architectural couture. Opening next month, the museum will be filled with contemporary art from Arnault’s personal collection and that of LVMH, and with a number of works created specifically for the building by artists such as Olafur Eliasson, Ellsworth Kelly, and Taryn Simon. (Ironically, the museum sits on the avenue du Mahatma Gandhi, named for the father of modern India who famously disavowed all worldly goods.)

Besides the idea of a garden pavilion, the architect was inspired by the 19th-century Bois de Boulogne itself, built under Napoleon III, with its man-made lakes and Grand Cascade. The glass-walled main entrance on the south side of the museum looks across the stone-floored lobby toward doors on the north that lead into the Jardin d’Acclimatation —the children’s park where, Gehry likes to think, the young Marcel Proust once played. Proust did write about walking around the Bois’s lakes, and the FLV is set in its own little pool of water, with a cascade that runs down tiled steps to the east of the building, outside the auditorium, one level below the lobby. The auditorium, which can seat up to 350 people in a flat or raked configuration, has glass walls on three sides; Ellsworth Kelly created paintings for the space, as well as a screen of colorful vertical stripes. The lower level also contains two large, flexible galleries and one small one, with poured resin floors (as in all the museum’s galleries); those rooms, like the auditorium, allow glimpses of the reflecting pool outside.

Off the main lobby is another big gallery, as well as a café and bookstore. Above the ground floor, in plan and section, the interior becomes particularly complex, with varied levels and half-levels and a number of circulation options (as well as dedicated fire stairs). The numbers of the floors sound like couture sizes: an elevator lists its stops as -1, -0, 0, +0.

One main stair is west of the entrance; another stair to the east is enclosed in a tower that exposes the gray steel armature supporting the exterior concrete panels—a backstage look at the building’s construction that feels like being inside a battleship. A glassed-in escalator on the north side of the museum provides close-up views of the exuberant exterior— onto a chunk of an iceberg, or inside a taut, curving glass sail, braced by the enormous steel and wood structural elements.

Up the stairs or escalator, seven more large and small galleries jockey for position on mezzanine and full-floor levels. The white, mostly orthogonal rooms were empty when this writer visited but will be filled with works by such artists as Christian Boltanski and Jeff Koons. They are not standard white boxes but designed so that no galleries are identical; several odd-shaped, intimate rooms are referred to as “chapels.” On the upper levels, the lofty galleries have a special grandeur; each features a skylight tucked up into an even higher softly sculpted cove, which casts beautifully diffused daylight. “We didn’t want to MoMA-ify it,” says Gehry, of the austerely regular galleries of New York’s Museum of Modern Art. In one spectacular space, half the gallery ceiling is nearly 30 feet high while the other half soars to 55 feet, with indirect light spilling down from a light well.

For some visitors, the peak experience may come upon leaving the upper galleries to emerge onto one of the multilevel terraces that top the museum. Here the sculptural forms surrounding the skylight coves pop up, and a visitor is enveloped by the ballooning glass sails—12 canopies composed of 3,600 unique panels of curved, laminated, fritted glass, mounted in stainless-steel frames, and supported by the elegantly joined steel and laminated-wood members. It provides one more close-up of the building’s luxurious, highly refined custom-crafting, without revealing all the mysteries of its construction. The elaborate placement of the sails’ supports—and the decision to include wood “for its humanity,” says Gehry—is expressive as well as structural.

Thanks to the ever-changing skies of Paris, the glass sails are constantly transformed—one moment transparent, and, the next, silvery opaque and reflecting the passing clouds. The steel and wood elements cast a network of shadows. And finally, from high on a terrace, the architecture becomes “a frame for the city,” says Gehry. The building opens up not only to the sky and the treetops but beyond, to Paris itself.