Volumes under slab

  • Shops
  • Equipments
  • Public spaces
  • On going

In short

Owner and investor: Paris La Défense
Architect (principal): Baukunst
Fluid techniques and economics: Setec
Stability: Greisch
Programming: Attitudes Urbaines
Urban planning: AWP
Design & acoustics: Studio DAP
Lighting designer: Licht Kunst Licht
Surface area: 20,000 sqm
Location: La Défense Axis of La Défense
Delivery of the pilot project: 2022


Continuity and porosity, the two "Ariadne's threads" of the project
A project with a triple coloration of uses: arts, events, and sports
Focus on the pilot project
Phasing of the pilot project
Financing the project

Historically, the Paris La Défense slab was designed to separate the functions intended for the users of the district from those of a technical or logistical nature. Thus, several tens of thousands of square meters in the basement are unexploited, representing :

350 m long,
13 to 70 m wide,
110 000 m3,
variable heights between 2.5 and 12 m.

Paris La Défense therefore decided to launch a competitive dialogue with international architects to imagine what will become of the 20,000 m² located under the esplanade, including the emblematic "Cathedral" space of more than 5,000 m², with the objective of creating new living spaces unique on the scale of the Île-de-France.

The proposal by the Belgian architectural firm Baukunst was selected in March 2020. It will be developed progressively, both in time and in space. Although the project has been thought out in a global manner, the complexity of the infrastructures means that it has to proceed step by step. Thus, the first phase, the pilot project, will concern the development of the Atelier Moretti and a part of the Cathedral with the objective of delivery by the end of 2021. This pilot project will foreshadow the rest, with the valorization of the other volumes at a later date.

The 4 spaces concerned by the project in the long term are the following

The Cathedral: 5,000 m². Height Under Ceiling (HPC): 6 m to 11 m
The Moretti Workshop: 2,240 m² HPC: 4 m to 12 m The FNAC: 4,480 m² / HPC: 2.5 m to 10 m
The Basins: 4,600 m² / HPC: 7 m

Continuity and porosity, the two "Ariadne's threads" of the project

To develop the basis of a program in permanent movement, the Baukunst agency follows two complementary axes:

  • the creation of continuity between the different spaces that are currently compartmentalized,
  • the optimization of the ≪ existing porosity ≫ between the slab and the lower levels.

Volumes under slab - Residual volumes project © Baukunst

The concretization of these principles involves two major achievements within the framework of the pilot project:

  • a public promenade evoking the Parisian passages. The backbone of the project, this walkway will distribute the successive volumes and join the Place Basse,
  • a monumental footbridge in the form of a ring ≪ floating ≫ above the Place de la Statue. Main entrance to the volumes, it will be accompanied by a qualitative landscape treatment. Interior gardens and biotopes will be linked to the green spaces of the slab by hoppers bringing in natural light in the image of a patio. An oculus will allow pedestrians on the Esplanade to observe the activity of the spaces below, and more particularly to offer a view of Le Monstre, a work by the artist Raymond Moretti.

Volumes under slab - Ring © Baukunst

The interventions will aim to decompartmentalize the spaces and maximize the possible porosities, in the medium and long term, with the other existing infrastructures such as Coeur Transport, the Centre Grande Arche parking lot or the Voie des Sculpteurs. This vision constitutes a tremendous opportunity for the project to be deployed on a large scale, creating several access points and attracting different players.

The project will also respond to the challenges of the city of tomorrow in terms of urban ecology, since it is based on the reuse of existing and irremovable infrastructures. The limitation of the number of emergences, the vegetal articulations with the surface and the minimal interventions within the volumes will facilitate the occupation of the future concessionaires who will be able to develop a complete program thanks to a phasing studied so as not to freeze anything.

A project with a triple coloring of uses: arts, events, and sports

The originality of the Baukunst agency's project is to reveal the potential of these forgotten spaces while allowing them to be reinvented. This explains why the programming of the volumes is not fixed, even if perspectives are emerging. A unique vestige of life in the basements of La Défense in the second half of the 20th century, Le Monstre, a work by Raymond Moretti housed in his studio, prefigured the development of the residual volumes. The artistic dimension, which appears as a major axis of staging of the place in line with its history, allows to give one or several shifted views and to recall its remarkable and fascinating identity. A great place of event and artistic expression will allow to preserve Raymond Moretti's work to make it visible to all. Mixed and dedicated to all the users of the site, the project will eventually also open up to leisure activities, with quality restaurants and wellness facilities, as well as to events and sports with indoor facilities.

Volumes under slab - View from Espace Moretti to Atrium © Baukunst

Finally, the overall composition will result in new urban atmospheres, both accessible and alternative. The volumes will take the form of an astonishing architectural walk, punctuated by games of light and shadow and unusual artistic and event experiences. Through these volumes, Paris La Défense will inaugurate a new perception of the district where one can work, but also live and go out, including evenings and weekends.

Focus on the pilot project

More than a simple prefiguration, the pilot project is a strong act that aims to create a momentum of appropriation of the place by all the inhabitants and users of Paris La Défense and will be the starting point of a bold, experimental, eventful and evolving program, in line with their expectations. It concerns the following volumes: the Moretti workshop and part of the Cathedral.

The inner life of the volumes will be signaled by the Ring, the Agam pavilion and the technical emergences of the project, giving a new dimension to the composite landscape of the slab. A walkway will wind from one site to the other and will allow access to the impressive volumes of the Cathedral and the Moretti Workshop where the Monster seems to await its visitors.

  • With the garden it dominates, the Ring is both the signal of the project and the main access to the "forgotten spaces" of Paris La Défense. It will combine a panoramic site, the animation of life on the surface, the arrival of natural light in the Cathedral and the access of people... From this weightless belvedere whose impressive size will be on the scale of the interior volumes, pedestrians will take an elevator, a monumental staircase and a double escalator. Suspended plants will accompany their descent, revealing the scale of the volumes.

Volumes under slab - La Traverse 2020 © Baukunst

  • Punctuated by landscaped chambers in contact with the surface, the underground walkway will wind its way through the heart of the infrastructures to a temporary staircase. Prefiguring a more complete walk between the Place de la Statue and Coeur Transport, it will allow, from the pilot phase, to discover the memory and the spirit of the place.

  • Visible from the promenade and accessible through an exit, the Caveau du Monstre and the Atelier will reveal the imaginary world of a district that is being rediscovered. Their role will be particularly important in the prefiguration phase to orient the programming of future concessionaires.

Volumes under slab - Cathedral 2020 © Baukunst

  • The Cathedral will be illuminated and can also be admired from the promenade. Accessible to a limited number of people at first, it will lend itself to temporary artistic experiments in view of future developments.
  • The Agam pavilion will echo the fountain and the green spaces of the slab. This building will have a technical function. Its upper part could be topped by an information screen or an artistic device illustrating the activities of the residual volumes.

Phasing of the pilot project

The technical, functional, legal and financial architectural actions will be carried out step by step, always preserving wide possibilities of evolution.

  • By the end of 2021, beginning of 2022: development of the spaces to make them accessible and "usable". Initially limited to the Atelier and part of the Cathedral, the interventions linked to the uses and programming will be progressive.

  • The development of the other volumes and the development of future activities will take place over the longer term.

Financing the project

The first artistic and event-based activities will aim to reveal the occupancy potential of each of the residual volumes. This unorthodox approach illustrates the establishment's desire to develop the district differently. Paris La Défense will invest 20 million Euros in this project and will be a player in the commercial programming of the spaces. This is a turning point in the history of land development: the establishment will not be satisfied with selling buildable surfaces, but will be the investor and promoter of these spaces responding to future demands and to a change in the market, in terms of use in particular, thus supporting the economy by mobilizing many actors in the construction and building industry.

Did you know ?

The Monster has resided since the 1970s in the dens of La Défense, and its development continued until the death of its master on June 3, 2005. Invisible to the general public today, it will be highlighted as part of the project to enhance the volumes.