Main challenges: the key dimensions that a sustainable city must address ............................ 41 A- Uncontrolled urban sprawl ...................................................................................................41 B- Environmental pollution and health .......................................................... ..............................42 C- Infrastructure and buildings .................................................................................................43 D- Actors and governance .......................................................................................................45 E- Citizens’ participation .........................................................................................................46 F- Stratification of wealth levels and areas of poverty .......................................................................47 G- Information and communication technologies ............................................................................ 47 H- Urban logistics ................................................................................................................48 I- Waste management ............................................................................................................48 List of Boxes, Figures Boxes 1.1 - The common good: definition .............................................................................................34 1.2 - Medellín in Colombia .......................................................................................................36 1.3 - Methodology .................................................................................................................49 Figures 1.1 - United Nations sustainable development – 17 goals to transform our world ....................................... 31 1.2 - Map of subareas related to the smart city concept .....................................................................41 1.3 - The Paraisópolis favela next to its wealthy neighbor, Morumbi, in São Paulo (Brazil) ........................ ..... 47 Sources ................................................................................................................................ 52 29 Quélin and Smadja | HEC PARIS | SMART CITIES | The sustainable program of six leading cities | 2021