Renowned French interior designer Jean-Louis Deniot has completed his most ambitious New York project to date, transforming a double-lot, six-story townhouse on the Upper East Side into a stunning showcase of contemporary luxury design. The 17,000-square-foot residence features custom furniture, rare vintage pieces, and carefully curated artwork that reflects Deniot's signature approach of blending traditional elegance with modern sophistication.

The sitting room exemplifies Deniot's refined aesthetic, where an Ugo Rondinone wall sculpture hangs majestically over a 19th-century French marble mantel. The space features a custom sofa upholstered in premium Pollack and Dedar fabrics, complemented by vintage pieces including a daybed and bird sculptures by Jacques Adnet. Additional highlights include a cocktail table and sconces by Ado Chale, a 1950s armchair by Maxime Old, and hand-painted wallcovering by Florence Girette, with artwork by Donald Baechler adorning the walls.

Since establishing his firm in 2002, Deniot has built an impressive international portfolio that includes a 17,000-square-foot triplex in Bangkok, a palace in Qatar, and a farmhouse in Delhi that resembles a miniature Versailles. His current projects span the globe, from putting finishing touches on the Cambridge House Hotel on London's Piccadilly to developing residences in Athens, Hong Kong, and Paris. However, New York has remained what he calls his "professional holy grail."

"It's not easy to make your mark there," Deniot explains. "You really have to buckle down and persevere." Despite maintaining a pied-à-terre in Manhattan for the past 20 years and completing several residential commissions, including a grand Fifth Avenue apartment and a Chelsea duplex in an Annabelle Selldorf-designed building, the designer has long sought to make a significant impact in the city.

This fall, Deniot will achieve that goal with the unveiling of his most high-profile New York project: the Waldorf Astoria Residences. He has designed 375 apartments and more than 50,000 square feet of amenities for the highly anticipated development. The units feature pared-down architectural elements inspired by the hotel's landmark Art Deco style, while amenities include a pool with raku-clad columns and mosaics inspired by kimonos and Gustav Klimt, a cork-wrapped billiard room, and a dramatic entry hall with towering marble columns.

"My hope is that the decor will end up being landmarked," Deniot says. "It corresponds so well to the Waldorf DNA." The project represents his determination to create something equally showstopping when he was approached to design the Upper East Side townhouse.

The entry of the townhouse immediately establishes the home's sophisticated tone, featuring a Calacatta Oro marble staircase with a wrought iron handrail inspired by legendary French designer Jean Royère. A vintage armchair upholstered in Pierre Frey fabric sits alongside a 1940s side table by Jacques Adnet, while artworks by Lee Krasner and Gregor Hildebrandt provide visual interest.

When conceptualizing the project, Deniot asked himself a fundamental question: "What should such a house look like today?" Through industry contacts, he gained access to several recent townhouse examples, finding some too brand-new and others slavish reconstructions of period styles. His solution was to create a balanced approach that honored New York's architectural heritage while incorporating contemporary elements.

"One of the things I concluded was there shouldn't be too much contemporary art, otherwise it becomes unlivable," he explains. "Each work screams for too much attention." He was also determined to celebrate conventional New York details such as bronze window frames, which he considers a quintessential city feature that introduces necessary formality. "It's not like we were in the East Village, where you could do something artsy," he notes.

The kitchen and family room overlook a carefully designed garden featuring a fountain sourced from Fremontier Antiquaires in Paris, with outdoor seating by Piet Hein Eek creating an inviting exterior living space. The dining room showcases a Hervé van der Straeten chandelier suspended over a custom table by Vincenzo de Cotiis, accompanied by vintage chairs and a sideboard by Gio Ponti, with artwork by Bernard Frize completing the sophisticated tableau.

However, "conventional" in Deniot's vocabulary doesn't translate to staid or boring design. He frequently establishes traditional frameworks for his rooms before "pumping up the volume" or introducing unexpected elements. The townhouse exemplifies this approach, where the grand staircase features a crisscross metal handrail inspired by French modernist Jean Royère, paired with eye-popping geometric patterns on the entry floors and walls. In one powder room, he counterbalanced an elaborate Italian baroque mirror with a striking black and white checkerboard floor design that playfully references New York's iconic taxi cabs.

The walnut-paneled library demonstrates Deniot's attention to both craftsmanship and curation, featuring a custom mantel in Grand Antique marble that displays 1940s vases by Charles Catteau and a candelabra by Georges Jouve. A custom sofa upholstered in Jean-François Lesage tweed provides comfortable seating, while artwork by Richard Misrach adds contemporary flair to the traditional setting.

The clients, a couple consisting of a financial services company founder and a strategic consultant and philanthropist, had interviewed numerous designers before discovering Deniot. "I did a ton of research on the internet, and his name kept coming up," the wife recalls. "I didn't even realize he was an established designer." The couple had previously lived for 20 years in the house that occupied the left half of the current plot.

"We loved it, but it just wasn't working for us anymore," she explains. "We had five kids, big entertaining spaces, and a tiny kitchen and family room." When the adjacent property became available, they seized the opportunity to purchase it. Initially planning to connect the two structures, they ultimately decided to demolish both buildings and start fresh when connection proved impossible. They commissioned Greenwich, Connecticut-based Anderson Kenny Architecture to design a new brick and limestone façade largely modeled on their former home.

The clients requested that Deniot incorporate their existing art collection as much as possible, which included significant works by Lee Krasner, Brice Marden, and Donald Baechler, plus a Kiki Smith drawing of a bird sitting on eggs. "That represents me and my five children," the wife explains. The collection also featured a large, curved André Arbus desk that found its place in the main sitting room, a Gio Ponti burlwood sideboard that inspired the library's walnut paneling, and a pair of blue leather-clad Jacques Adnet chests.

Deniot complemented these existing pieces with special commissions from contemporary design stars including Hervé van der Straeten and Vincenzo De Cotiis, while also incorporating signed pieces from the same periods. His approach includes what he calls "uninhibited design," a high-low methodology that mixes prestigious pieces with more accessible finds. Though he's known to integrate garage sale discoveries or street finds in some projects, he took a more refined approach for this residence. "I often compare my rooms to a film, where you need both lead actors and extras," he explains.

The basement swimming pool creates a spa-like retreat, enclosed with Verde Antigua marble, polished stainless steel, and mirrors that reflect light throughout the subterranean space. This amenity represents the kind of luxury accommodation that transforms a private residence into a comprehensive lifestyle environment.

Working with the decisive clients proved to be a collaborative and inspiring process that Deniot describes as "like a game of ping-pong." The wife's visit to the Hermès flagship store on Rue du Faubourg Saint-Honoré in Paris, where she admired the handrails, provided the starting point for the back staircase design. Her fascination with the reconstruction of Jeanne Lanvin's bathroom at the Musée des Arts Décoratifs led Deniot to clad one powder room with wallcovering named for its designer, Armand-Albert Rateau.

The design process involved extensive travel and research, with trips to Italy for marble selection, visits to Jean-François Lesage's Normandy fabric workshops, and tours of photographer Katerina Jebb's Paris studio. The team also made countless expeditions to Paris's flea markets, which Deniot describes as "a big candy store" for discovering unique pieces that add character and history to contemporary interiors.

"I couldn't imagine collaborating with another decorator," the client reflects. "My eye became much more refined from working with him. He's really brilliant, but more than brilliant, he's just so much fun." This sentiment captures the essence of Deniot's approach: combining serious design expertise with an infectious enthusiasm for creating spaces that are both sophisticated and livable, marking his successful conquest of the New York design scene he had long sought to master.