According to the Intergovernmental Panel on Climate Change (IPCC), acting against climate change while protecting nature is essential to ensure a viable future. Urban areas, where 55% of the world's population lives, are particularly vulnerable to climatic (extreme events, systemic crisis) and environmental (air pollution, heat waves, noise) risks. Faced with this situation, there is no inevitability: adapting urban environments to new climate challenges, reducing road traffic, encouraging active mobility such as walking or cycling and developing green spaces are all accessible and effective climate, biodiversity and public health friendly strategies. These initiatives represent major action points for local authorities, but strong determination in terms of intersectoral collaboration is required in order to achieve real transformation within cities.