On November 24, 2015, the TRANS-FAIRE agency once again took part in the Master Environnement et Développement Durable at the Institut de Géographie (Université Paris 1 Panthéon-Sorbonne), for a course dedicated to urban ecology. We developed the agency’s approach to taking biodiversity into account in the city. Rather than the classic project/impact/measure diagram, we prefer a diagnostic/ecological programming/parametric approach sequence, in line with the avoid, reduce and compensate (ERC) philosophy of the French Environment Code. Biodiversity is taken into account in the service of comfort of use. We presented concrete examples of application, on the scale of large territories, neighborhoods and buildings.