Huge helical staircase emblazons French pavilion at Expo 2025 Osaka

A lush secret garden is among the spaces to discover inside the France Pavilion at Expo 2025 Osaka, which French firm Coldefy and Italian studio Carlo Ratti Associati have fronted with a giant copper staircase.

Positioned on a wedge-shaped site beside the USA Pavilion, the structure has a reusable steel frame and draws on references ranging from romance and connectedness to theatre architecture.

Its focal point is the winding copper-clad staircase, which defines the front elevation and rises to meet an observation deck. This is a nod to the Japanese legend Akai Ito, which suggests that people destined to meet are tied by an unbreakable red string.

It is also intended to evoke grand staircases in theatres, matching the design of the 17-metre-high white fabric facades that flank the pavilion and are modelled on stage curtains, according to Coldefy and Carlo Ratti Associati.

"The staircase is one of the pavilion's most visible and dynamic elements," said Coldefy founding partner Thomas Coldefy.

"Beyond its functional role, the staircase contributes to the project's conceptual narrative," he told Dezeen.

"It draws from the language of theatre, referencing the grand staircases found in performance spaces, reinterpreted here as an open, sculptural element."

The helical staircase also guides the pavilion's circulation, drawing visitors up to the top of the building before descending back down as they navigate the exhibits, and concluding at ground level.

"It becomes a stage in its own right, where the movement of people animates the pavilion," added Coldefy. "In that moment, the visitor is not only observing the space, but also becomes part of it – part of the architecture, part of the scene."

The ambition for the staircase is also for it to encourage visitors to interact and connect, added Carlo Ratti, founder of Carlo Ratti Associati.

"We aimed to use architecture to foster these moments of connection among visitors," Ratti told Dezeen.

"This inspired the concept of the staircase as a 'human condenser' – a design idea we've explored in other projects, like the MEET Digital Center in Milan, where vertical circulation spaces are designed to encourage meaningful, in-person exchanges," he continued.

"The importance of coming together in space has never been more urgent," he continued. "Unlike online platforms, public spaces have the unique quality of inevitability – they bring together and promote interactions among people from all walks of life."

Coldefy and Carlo Ratti Associati developed the design in collaboration with project commissioner Cofrex, which asked for the pavilion to include exhibition space as well as a bakery, shop, VIP room and office space.

The exhibits have been curated under the title Pulsations, led by artist Justine Emard with design studio GSM Pro. Installations include a sculpture salvaged from Notre-Dame, a room showcasing the history of Louis Vuitton by OMA and a Lady Dior handbag designed by SANAA co-founder Kazuyo Sejima.

There is also a secret garden, featuring a 1,000-year-old olive tree transported from France, which is surrounded by a pool of water.

"If the French Pavilion is about connections, then nature must be part of that conversation too," said Ratti.

"This space reflects the project's broader message of interconnectedness between people, environments, and other forms of life," added Coldefy.

"Positioned behind the opaquer exhibition volumes, the garden introduces light, air, and a slower pace, reminding visitors that architecture is also a frame for relationships beyond the built."

The France Pavilion was featured among our roundup of ten stand-out pavilions at Expo 2025 Osaka, which takes place on Yumeshima Island in Osaka Bay until 13 October.

Like the majority of pavilions at this year's event, it is designed to be fully demountable and reusable, with a steel structure and modular plug-ins for the office areas. This also ensured quick construction and a lightweight framework, which Ratti said was "necessary due to the soil conditions at the Osaka site".

It is among the pavilions encircled by The Grand Ring, the world's largest wooden structure, designed by Sou Fujimoto Architects.

The photography is by Julien Lanoo unless stated otherwise.

Expo 2025 Osaka takes place in Osaka until 13 October 2025. For more fairs, events and talks in architecture and design visit Dezeen Events Guide.

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