The localization of the service centre on this parcel meets two major targets: One is to mark one of the main entrances of the joint development zone Eurasanté coming from the north-south axis between Lille and the southern part of the agglomeration. The other is to provide the area, in its present configuration and taking into account its future development, with the necessary accommodation services, shopping facilities and restaurants as well as with workshops and recreational facilities. The building is situated at the junction of the two baseline routes of the joint development zone East, a square which is supposed to become a major public space for the area and a planted garden in the centre of the block. The volume respects the alignment of the streets and the square and guarantees the urban aspect of the building. It"wraps" around an amenity space (upper terrace) in connection with the landscaped pool. The eastern façade follows the pedestrian promenade in its oblique trajectory along the landscaped pool. The fact that the parking lot is situated on an upper floor lifts the project off the ground and makes it « fluid », yet dense. The different types of openings reflect the diversity of the activities that can be found in the building. They are also defined according to the energy performance, i.e. exposure to the sun, solar contribution, natural ventilation, etc. The façades a treated in a sober manner, made of metal lacquered cases in light, homogeneous colours. The façade of the ground floor, destined for commercial use, consists of different frames. Their flexible structure allows to absorb variations and adjustments in the future. The architectural choices aim to combine the expression of an urban space that is supposed to play a key role in the urban design of the joint development zone and the expression of the mixed usages reunited in the building. The diversity of the types of openings and the expression, after all very distinctive, of the four façades contrast with the simplicity of the outer coating (homogeneous materiel and colour). The aim of the program in terms of energy also determined the functional organization, the volume and all the technical aspects of the building. With a gross floor area of almost 14 000m ², the compact form of the building guarantees the energy efficiency of the different programs. The functional organization is directly related to the orientation of the façades based on their exposure to the sun and prevailing winds. Each façade is treated appropriately. Sizes of the bay-windows bays and sunscreens are suitable for the different functions and objectives of the project in terms of energysaving. The interior garden that covers the parking lot located above the retail spaces accessible from all programs. Playing an important role in terms of security for the evacuation of the occupants, it also contributes to the user-friendliness. Waste processing operations, water management (in this case, the water is discharged into a landscaped buffering pool conceived by SEM SORELI in the context of the joint development zone’s public facilities) and transport are themes which, although less directly related to energy, are discussed and integrated into the approach of the project.