Public inquiry

The public inquiry related to the Building Permit of the Sisters Towers took place from Monday 14 November to Friday 16 December 2016. The conclusions of the public inquiry are available here.

Characteristics of the project

Why is the project named Sisters?Flèche de déroulement de la question
The project intends to belong to a new generation, at a human scale. Due to their shape, the two towers look like two sisters holding hands: an older sister and a younger sister.
Where are the Sisters Towers located?Flèche de déroulement de la question
Place Carpeaux La Défense is Europe’s number one leading business district and is the largest employment hub in Ile-de-France. Sisters is located right at its heart, on Place Carpeaux, in between two iconic buildings, the Grande Arche and CNIT. Plan de la situation des deux tours Sisters au sein de la Défense à Paris
What is the design of the Sisters Towers?Flèche de déroulement de la question
The footprint limited and constrained by roads and railways defines both the constructability and the design of the project. The two towers have to extend beyond the perimeter of their foundations. They develop a cantilever facing Place Carpeaux, appearing as three curled leaves that seem to emerge from the sky, echoing the CNIT vault. Schéma de l'intégration urbaine des deux tours Sisters au sein de la Défense à Paris
What activities will be developed within the Sisters Towers?Flèche de déroulement de la question
The project is made of two towers connected by a deck:
  • • A tower called « T1 », of a height of 219 meters hosting offices and services;
  • • A tower called « T2 », of a height of 110 meters hosting a 273 key 4* hotel and 36 serviced apartments;
  • • Le Deck, run by the hotel includes a large and versatile room (the Ball Room) that can be turned into an auditorium or a banquetting room. It also features a restaurant and a panoramic bar, a business center, a wellness center and a swimming pool.
How to access the Sisters Towers?Flèche de déroulement de la question

For pedestrians // With public transport:

According to a study on "Transport Mobility at La Défense" carried out in 2014, 87% of employees working at La Défense use public transport to commute to their work place. Only 6,7% use their car.

The Sisters Towers will benefit from excellent connections to public transport since they will be located next to the transport hub of La Défense, which will be reinforced by the extension of the RER E "EOLE" under the CNIT expected to be delivered in 2022.

Pedestrians will have access to the two Towers at the level of Place Carpeaux since the twho towers will be located on one side and the other of the Carpeaux footbridge. The layout is intended to create a strong urban link in particular with the reorganization of Place Carpeaux that will be implemented by the EPADESA.

For bike riders:

Bike storage rooms (total capacity of 153 places) will be available in both towers:

  • • In the office tower, it will be accessible both from the slab level and the Demi-Lune Road level ;
  • • In the hotel tower (for employees' use), it will be accessible from the Demi-Lune Road level.
Bicyle parking spaces will be also available in public spaces.

Plan d'accès et de stationnement des tours Sisters à la Défense

For car users:

The Sisters Towers benefit from the already existing connections in La Défense: Boulevard Circulaire, RN 13, and A14. Given the very constrained footprint of the building, only 4 visitor parking spaces are available in the office tower (in addition to the delivery and waste removal zones). Personal car users will be able to park either in the Coupole-Regnault parking where they will benefit from the 70 parking spaces agreed upon long-term concession contracts or in other parkings of La Défense located nearby. On another note the existing taxi connection on Carpeaux Square will be maintained and reorganized by the EPADESA.

What environmental ambitions will be developped within the Towers project?Flèche de déroulement de la question

The Sisters Towers aim at environmental excellence throughout their life cycle (design, construction, operation). They aim at the highest levels of certification of the market:

  • ● HQE™ NF Bâtiments Tertiaires (French certification);
  • ● BREEAM™ International certification;
  • ● WELL™ certification applied to offices.

Furthermore, the project will comply with the “Better places 2030” CSR approach presented in September 2016 by Unibail-Rodamco group, aiming to significantly reduce the carbon footprint linked to the construction and operation of the buildings.

“Better places 2030” CSR approach
What is the provisional roadmap for the implementation of the project?Flèche de déroulement de la question
  • ● 2017: procurement of the building permit and launch of the site's preparatory works
  • ● 2018: launch of towers construction works (duration: 40 months)
  • ● H2 2021: delivery of the project

The impacts of the project

How will Place Carpeaux and footbridge be affected by the project ?Flèche de déroulement de la question

The Sisters Towers' new program allows for the Carpeaux Footbridge to remain accessible, including during the construction works. The design of the towers is adapted to meet this requirement : after the project delivery, crossing the Carpeaux Footbridge will be a unique experience in itself.

In particular, the urban animation of Place Carpeaux and the footbridge will be at the heart of the project, whether with the transparently glazed halls accessible directly from the Square, or with the restructuring of the footbridge's surroundings, and a convenience store created in the hotel tower, as well as rest spaces and landscaping currently being studied by the EPADESA.

What will become of the current facilities installed on the project site?Flèche de déroulement de la question

The EPADESA will carry out a complete redevelopment of Place Carpeaux, that will nonetheless keep César's "Thumb" and Miyawaki’s "Utsurohi" as well as the taxi station.

Under the square, the section of the site located at the East of the Carpeaux footbridge comprises two electrical transformer posts in close proximity (one being used by the SNCF, the other one by the RATP).

The implementation of the project involves the demolition of the SNCF electrical transformer substation (located on the site of the future hotel tower) to be transfered onto premises situated in close vicinity, under the Boulevard Circulaire. On the other hand, the electrical substation used by the RATP is not affected by the project.

How will the project affect sunlight and wind conditions ?Flèche de déroulement de la question

Specific studies were carried out by the CSTB, an independent public organization, to assess the impact of the Sisters Towers on the amount of sunlight that other surrounding buildings benefit from and on wind conditions.

Regarding shadows, this study concluded that the project will have limited and localized impact on maximal lighting conditions of certain surrounding buildings. With regards to wind conditions, the studies show that even though in specific surrounding public spaces (especially at the center of the Carpeaux footbridge) wind speeds superior to the threshold of discomfort felt by pedestrian should be experienced more frequently than today, the frequency should however remain at acceptable levels given the types of use of these spaces. However the project will have positive effects on the public space located at the North of the footbridge. The “Environmental impact report” and its addendum contain graphic documents that show the impact of the project in terms of solar lighting.

The construction site

How will pedestrian traffic will be managed during the construction work?Flèche de déroulement de la question

The worksite organization has been designed to take into account the constraints of the site and the guidelines defined by the EPADESA, in particular the ”Cahier des chantiers à faibles nuisances”.

Impact on road traffic:

  • Planking protection allowing to flyover the Boulevard Circulaire with the construction cranes
  • Immobilisation of one lane of the Boulevard for the construction site deliveries
  • Reduction of the Demi-Lune Road: implementation of a two-way traffic managed with traffic lights

Impact on pedestrian traffic: the pedestrian traffic is maintained on the Carpeaux Footbridge, including during the construction work. Some adjustments involving a protective planking and temporary width reduction will be carried out in order to ensure the security of the pathway.

Phase 0: The gateway is entirely maintained (24-meter width) during the infrastructure works (9 months)

Schéma de la passerelle pendant la phase 0 des travaux des tours Sisters

Phase 1: Bridge maintained over 19m wide during the elevation of the first floors (7 months)

Schéma de la passerelle pendant la phase 1 des travaux des tours Sisters

Phase 2: The bridge is reduced to 12 meters for 2 months to allow the construction of a protective platform, prior to the higher level work.

Schéma de la passerelle pendant la phase 2 des travaux des tours Sisters

Phase 3: the total width of the bridge is made public again, once the protection platform is installed at a height of 6m. It protects against nuisance (dust, noise) and public lighting is installed under the platform.

Schéma de la passerelle pendant la phase 3 des travaux des tours Sisters
Which commitments are being made to minimise the nuisance associated with the construction site?Flèche de déroulement de la question

A number of actions, taken from EPADESA's ”Cahier des chantiers à faibles nuisances” as well as from the environmental labels aimed at in the project, will minimize the impact of the works on their direct environment. In particular, the cleaning of the construction site and its surroundings will reduce the visual impact and thus reduce the discomfort felt by the local residents and other users (employees of the neighboring buildings, visitors, tourists, etc...).

Our commitments for the site's management:

  • • Minimize the visual impact of the construction site;
  • • Avoid disturbing pedestrian and vehicle traffic;
  • • Avoid any land or water contamination ;
  • • Establish time slots to manage noise and vibrations;
  • • Proper management of the site;
  • • Use of pre-manufactured materials;
  • • Avoid dust dispersion: partioning of working areas, watering of the ground during the summer, use of tarpaulins on trucks;
  • • Maintain the cleanliness of the roads : washing of wheels at the exit of the construction site, cleaning of access points and removal of any mud (maintaining the cleanliness of the road network).

Giving information to local residents:

  • • Information about the ongoing construction works on this website as well as on social networks;
  • • On-site mailbox and display system to collect requests or observations;
  • • Organization of site visits ;
  • • Information about the works' progress and in case of any exceptional works;
  • • Participation in EPADESA's construction site steering commitee, which takes place every two months in La Défense;
  • • Monthly newsletter summarizing the progress.

Waste Management, sorting and recycling

Waste is sorted on site in order to promote their recycling. Target: to recycle 70% of waste (in bulk)