SENLIS, FRANCE.- For many architects, time is measured in projects, and when Dominique Perrault and Gaëlle Lauriot-Prévost — partners in life and in the firm of Dominique Perrault Architecture — went looking for a weekend country house outside Paris, they were looking, Perrault said, “for a balance between city and nature.” But they really weren’t thinking about a cozy farmhouse needing a little TLC. They wanted something more ambitious, something with scope, perhaps an architectural cause. They were looking for a “project,” he said, “because our life is a project.”

They were already used to making “no small plans,” as American architect Louis Sullivan once advised young architects. In 1989, early in his career, Perrault — then 36 — won a competition to design and build the treasured National Library of France in Paris. Perrault Architecture is now master-planning the 2024 Olympics in Paris, which includes transforming a largely abandoned industrial district along the Seine for the Summer Games.

For their weekend getaway, the couple first considered reworking an existing structure such as a small, disused factory. But a real estate agent specializing in architect-designed properties led them to a modernist gem that had, somehow, been forgotten. Neither Perrault nor Lauriot-Prévost, herself an interior architect, had ever heard of it.

During much of the 20th century until his death in 1965, Swiss-French modernist Le Corbusier sucked up most of the architectural oxygen in France. But there were other talents, some major — among them Jean Dubuisson (1914-2011). This third-generation Parisian architect came out of the traditionalist École des Beaux-Arts to design modernist housing blocks that — like highways and airports — helped build the infrastructure of a country climbing out of World War II. Many of his blockbuster apartment buildings were created for Parisian developer André Weil, who hired Dubuisson in 1966 to design his own country house on a large property of rolling hills, the Domaine de Frapotel, set within a protected forest near the medieval town of Senlis, north of Paris. It was finished in 1968.

The house, however, immediately fell between the cracks of history. Perhaps the 7,500-square-foot villa was overshadowed by Le Corbusier’s more famous houses. But the student rebellion of 1968 in Paris — the historic Events of May — traumatized the French architectural world, which subsequently questioned the cold, abstract formalism of modernist architecture within a larger postmodernist critique of consumerism. Champions of postwar progressive culture like Dubuisson had their faith in modernism shaken, and lost their architectural bearings. In the six decades since, fogs of time closed in on the Villa Weil.

But what Perrault and Lauriot-Prévost first saw as they drove through the wrought-iron gates and up the elliptical drive was the pure, straight line of a building streaking across the landscape, a taut geometric abstraction that, in their eyes, after 50 years, had broken intellectually free of the lingering cultural baggage of 1968. With the distance of time, it was fresh again. The long, low, single-story house at the top of the rise owned the property like a chateau, “but a flat chateau,” Perrault said. The driveway bounded a wide lawn that recalled the cours d’honneur of chateaus, but without the cobblestones and ostentation.

The agent, an architect, introduced the couple to the aging house, on life support then, in the company of Dubuisson’s son François, also an architect. The danger was that a developer would steamroll the house to exploit the many acres of the expansive estate. “The moment was emotional because the house seemed vulnerable,” Lauriot-Prévost remembered, speaking recently over a simple lunch of goat cheese and salad she had prepared in an intimate family dining room in the house. “It was empty, and it looked a little like a ghost house because it was totally white, inside and out.”

According to Perrault, François Dubuisson, protective of the unique building, cautioned: “It is impossible to work with this kind of architecture design if you don’t like it. You will destroy it.” Its geometric purity made it especially vulnerable to compromise.

Jean Dubuisson, who, through his large housing projects, aimed at elevating the lives of people who themselves could never afford an architect, transposed his idealism to the villa, keeping it as simple and clean as a diagram in a geometry book. The horizontality itself was a social statement: Without a second story, there was no upstairs/downstairs divide of servant and served. Nor was there any decoration in a design ultimately based on an aesthetic of the machine — then thought to be an agent delivering social progress affordably. A clean, white band formed the roof line, matched by a corresponding clean, white band at the floor line. The two lines defined a void in between, where a continuous wall of sliding panels, fore and aft, opened to gardens between the facade and the rooms.

Weil, who commissioned for himself what he had built for the average household, came to the idealistic challenge of rebuilding France with an unusual background as a high-ranking fighter in the French Resistance. At the war’s conclusion, according to Weil’s account in the publication Le Patriote Résistant, he stood with Charles de Gaulle at the Gare de Lyon welcoming deportees returning from concentration camps (some were then lodged at the luxurious Hôtel Lutetia, once headquarters for Nazi counterintelligence).

Paradoxically, the floor plan at the Domaine de Frapotel is as ceremonial and formal as a chateau’s. A vestibule with a white marble floor opens to a corridor aimed straight out to the back, with a long view of a landscape that drops to the valley below. An axis divides the house symmetrically, while a perpendicular one separates the house into front and back. Equally sized rooms for a small staff and children line the front quadrants, each with a bath and private garden, while an expansive living room flows into a large dining room, with a roomy nearby kitchen. The master bedroom suite, with a small family kitchen and dining room, occupies the last quadrant. No social coding of finishes and materials distinguishes between front and back of the house — the architects used the same tiles in all the bathrooms. The house may be grand, but its floor plan and straightforward attitude advocate domestic democracy.

Inside and out, the clean white planes, crisp machined corners and squared geometries are derived from International Style modernism and recast into a new synthesis. Front and back, the white roof and floor lines and space dividers between the terraces form a spatially expanded version of the sun breakers that Le Corbusier built on his facades. The abstract lines and planes, like picture frames, bracket terraces landscaped like the Zen gardens Dubuisson had seen in Japan. Huge sliding glass doors recall the indoor-outdoor relationship of midcentury modernist California houses, by then well known in Europe. A sense of French Cartesian order thrums through the house.

Reinventing precedent, Dubuisson built a manifesto for a renewed modernism in France, a livable health house with the grace of a chateau but the egalitarian spirit of social housing.

Now Perrault and Lauriot-Prévost live in the house informally, with their two dogs. Lauriot-Prévost furnished it, appropriately, with midcentury modern furniture bought off the internet. During COVID-19, the couple worked remotely from the big dining room, appropriating a long oak dining table as their desk.

What makes the house a project, however, is not simply its size, pedigree and stature. There’s a large basement and, nearby, a horse barn, both of which are being outfitted as exhibition spaces and archives for shows and their office’s vast library of models and drawings. Next to the cast-iron entrance gate, former apartments for a concierge and gardener will host resident artists, architects and researchers as part of a study center that will help make the estate the host of conferences and public events.

Architects are famous and infamous for expanding a task to its fullest potential, and at the Domaine de Frapotel, Perrault and Lauriot-Prévost are investing a weekend house with a semipublic program that will expand the life of a private villa into a campus for a larger architecture and design community.

“We met this masterpiece and fell in love with it,” Perrault said. “And it became our project.”

This article originally appeared in The New York Times.