Introduction to the special issue "Urban Planning and Health-Promoting Development," coordinated by Zoë Heritage, Director of the WHO French Network of Healthy Cities; Anne Roué-Le Gall, Lecturer and Researcher in the Department of Health, Environment, Occupational Health, and Sanitary Engineering at EHESP in Rennes; and Christine César, Scientific Advisor in the Directorate for Regional and Network Coordination at INPES.