Faced with the expansion of 5G and the challenges of 6G, energy restraint and exposure to electromagnetic fields are becoming major issues for the networks of tomorrow. Between optimizing infrastructures, mobile sensors and prediction models, scientists are striving to reconcile performance, lower consumption and quality of service. Just Enough Network, a project co-led by Télécom Paris, is therefore trying to build networks that are ‘just enough’ to meet our needs, without surplus or wastage.