This Hyper

"We turned everything upside down," says Uchronia's Julien Sebban.

A young, worldly couple moves into a classic Haussmannian building near Paris's Champs-Élysées and is faced with a choice: stay true to its 19th-century character, leaning into the high ceilings, marble mantels, and gracious rooms, or throw caution to the wind. One glance at its color-saturated rooms and it is evident which route this couple chose.

It was Julien Sebban, the Paris-born founder of the four-year-old firm Uchronia, who helped the homeowners to demolish their comfort zone. Sebban, who was based in London for six years to study architecture, has quickly made a name for himself with spaces that tap into the zeitgeist with abandon. Most notable may be the restaurant Forest, opened last year at the Musée d’Art Moderne de Paris, and before that, Créatures, a pop-up eatery atop the Galeries Lafayette that's since become a seasonal staple of the city's dining and social scenes.

The firm's name is itself a neologism taken from Uchronie, the title of a book written by 19th-century French philosopher Charles Renouvier, referring to a hypothetical time period of our world. Sebban's multidisciplinary collective, then, is something of an anachronism, straddling our current moment and some whimsical, acid-tinged version of it hovering just beyond the scope of our peripheral vision.

Uchronia's signature use of outsize motifs, undulating lines, bright colors, and pattern have made each of its projects an instant social-media star. "The homeowners wanted to keep the idea of a traditional Haussmannian apartment, but with crazy details," says Sebban of the 2,600-square-foot space, situated in the tony Triangle d’Or district in the city's 8th arrondissement. "So we kept the original layout and the floors but turned everything upside down."

The homeowners are both involved in the world of luxury and often entertain; their space needed to be designed to suit this lifestyle. Beyond that, they wanted everything to reference jewels and stones. "We imagined walking into our jewel box, each gem blown up to an architectural scale," the wife says. "That is exactly what we got."

For Uchronia, this was a point of departure. The firm's prodigious use of curves wouldn't cut it—quite literally, in this instance, as the clients wanted elements of the interior to look faceted, like gemstones. To create that feeling, the firm focused on the details: a mirror was added above the mantel, layers of Japanese gold leaf inset along its edges in emerald and aquamarine tints; custom hardware was designed to reference different stones—malachites, sapphires, opals, and rubies; painted silk curtains, color-matched to each room's jewel-toned walls, were specially commissioned from the artist Justin Morin.

The dining room table was made in seven pieces so that it might be pulled apart. It seats 16, and the center can be removed and used as a side table for serving. All in all there are 40 legs, each of which is treated like a piece of jewelry, rendered from hammered steel. In the kitchen, the firm designed and fabricated its first-ever stained-glass windows; elsewhere, a custom dégradé wall treatment (a gradient color scale that, unlike ombré, allows for a range of hues) was developed in collaboration with Atelier Roma and deployed in the living room in blue and in the dining room in a mossy green. "Where it was once banal," the wife says, "it is now magic."

The clients eschewed editions; the apartment is furnished with vintage finds from auctions and the Paris flea market, alongside custom Uchronia pieces. In total, the project took seven months devoted exclusively to design and decoration. "Their free spirit spoke to us," the wife says of Sebban and his team. "When we met Julien, we knew that he could translate our specific interests, our desires, our way of living into a wonder-filled home that felt like us." What could be more classic than that?

This story originally appeared in the May 2023 issue of ELLE DECOR. SUBSCRIBE

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