Construction of an ecological, vertical, high-density data center. This global innovation consists in creating server towers, cooled down thanks to a "free-cooling direct" system (using the external air to reduce the temperature of the computer rooms). This vertical design encourages the stack effect of the tower ("chimney effect"), it limits the footprint of the building (extremely useful in areas with tensions related to land) and it clearly reduces the construction and operation costs (important reduction of linear networks). This concept was executed in Champs-sur-Marne with the construction of a Celeste data center, built in 2012. International patent. In partnership with Celeste.