Active design aims to develop public spaces that spontaneously encourage users to play sport or more modestly to be physically active on a daily basis. Through nudges in public areas, it fosters people to move and do sport without noticing. Positive and rapid actions can make these areas more attractive, whether by encouraging physical activity or by targeting specific users : for example designing playgrounds around schools, designing tourist itineraries in heritage areas, providing information on walking time and direction of public transport, or even creating rest areas to make it easier for the elderly to move around... Active design is not just a tool for improving public health, it is a new way of designing public spaces that can have multiple leverage effects to positively transform the city.