From the Louvre and the Arc de Triomphe du Carrousel to the Grande
Arche de la Défense, the Historical Axis in Paris is a walkable 10-kilometre
stretch of architectural and cultural significance. So in order for a new
building to make any sort of impression, it must possess a little something
special. Case in point, the recently completed InDéfense and
Hôtel OKKO; it now anchors La Défense — the westernmost region of
the Axis and Europe’s largest purpose-built business district — which
dates back to the 1950s.

As the first structure you see when you enter the neighbourhood,
it needed to be an “eye-catching and dynamic” standout. This aspect
was top of mind when Danish architecture firm 3XN began designing
the 16,000-square-metre mixed-use project (its first in France), which
was commissioned by developer Vinci Immobilier and executed in
partnership with French firm SRA Architectes.

An agora with a spiral escape staircase links the two buildings, supplying bike parking for the occupants and open views to passersby.

Though the two buildings serve different purposes — as an office
space and a hotel — the firm wanted them “to work together but be
diverse, to have their own identities,” says 3XN founding partner Kim
Herforth Nielsen. To achieve this, the architects clad each in the same
material — aluminum — but applied different finishes: a warm matte
bronze (AluCopper from Alumet) and a cool mirrored silver (anodized
Aloxide from Coil), respectively.

Working with French high-tech facade manufacturer Rinaldi Structal,
the team devised a series of prefab cassettes of varying sizes for the
unitized envelopes (10 for the workspace and three for the hotel, plus
modules for the roof, corners, terraces and ground-floor structure),
arranged in a rhythmic checkerboard pattern. Their angles change
depending on what level they are on, self-shading the buildings by controlling
the amount of direct sunlight that reaches the interior. Perforated
side panels on the office building’s cassettes neatly conceal the
ventilation system, which can be accessed via clean-lined doors inside.

3XN staggered the different volumes of the office building (clad in bronze) to add another dimension and create shaded overhangs and sun-bathed terraces.

To create that required strong street presence, frameless windows
alternate with the metallic elements to lend an artful play of transparency
and opacity. “Both facades change throughout the day, depending
on time, weather and where you are in context with the building,” says
Herforth Nielsen. “It has a lot of life and energy.”