Cristal Riviera is a competition proposal by French firms Périphériques Architectes, a/LTA architects and Hamonic & Masson. It is a response to current developing renovation and regeneration program around Rennes Railway station in France, which asks for an improved urban circulation and connectivity within the whole of the city.

The Féval city-block is a significant part of the renovation program performed around the Rennes rail-station. The urban project is developed by FGP and Territores. The program suggests developing of a new territory to connect the two sides of the city, while involving changes in landscape and topography. The railway road passes through urban structures like a river would pass through giant tectonic monuments in a form of large crystals.

Three buildings that form a project are made by three different architects, and the whole project is structured around a landscape rift. The crystal structure is carved very precisely in order for sunlight to reach the inner territory.

Success of the Féval city-block heavily depends on the quality of the infrastructure on the ground floors of the three buildings. The architects paid particular attention to increasing accessibility to the inner spaces from the outside. They defined a section of the office by calibrating floors to 3.40m slab to slab. Savings in the height of each floor added up to one additional floor for the 28m building.  This solution created a large area which enables the flexibility to cut large volumes in order to produce fancy crystal-like shapes making all composition more spectacular. This ability to resize volumes allowed the architects to create a valley where the three buildings meet on the Féval Street and allow daylight to enter into the center of the block.