Construction21 is a social media dedicated to all professionals active in the building and city sectors and interested in sustainability. Our objective? Get the vast majority of city stakeholders to adopt innovation and best practices of pioneers by making them known both at a national and international level. It is a collaborative platform that spreads free information and good practices from sustainable building to sustainable city actors. It is also a social and collaborative media that accelerate the sharing of innovative solutions to address climate and decarbonization issues.