The Stream Building, PCA-STREAM's manifesto project, is located at the heart of the new Clichy-Batignolles district in Paris. The project integrates 15 years of research, conducted by PCA-STREAM, on innovations addressing the key challenges awaiting the cities of tomorrow. Circular by design, the Stream Building is a productive and resource building concentrating all the activities of a vibrant urban life. Mixed in its uses and in its timber-concrete construction, the project draws on the environmental qualities of wood to limit its carbon footprint and create a modular, reversible framework.