In this episode, journalist Laurence Garcia meets sociologist and town planner Alain Bourdin. This professor at the École d'Urbanisme in Paris and Director of the journal Revue Internationale d'Urbanisme, is also the Scientific Director of the POPSU2 project studying ten cities in France to devise the smart city of the future. Together, they consider what makes a city ‘smart’ and the challenges it faces. Alain Bourdin encourages us to conceive of a new urban model helping people enjoy life side by side in a future where, by 2050, cities will contain another 3 billion inhabitants, and transport methods will be radically transformed.