According to the Intergovernmental Panel on Climate Change (IPCC), it is essential to take action against climate change while protecting nature in order to ensure a sustainable future. Urban areas, where 55% of the world’s population lives, are particularly vulnerable to climate-related risks (extreme weather events, systemic crises) and environmental risks (air pollution, heat waves, noise, sedentary lifestyles, etc.). Faced with this situation, there is no inevitability: adapting urban environments to new climate challenges, reducing road traffic, promoting active mobility—such as walking or cycling—and developing green spaces are all accessible and effective strategies that benefit the climate, biodiversity, and public health. Overall, local governments thus have significant levers for action at their disposal, but these require a strong commitment to multisectoral collaboration in order to literally transform cities.