The ClouT project sees a group of European and Japanese organizations coming together to cooperate in building tools and applications for cities and their citizens. ClouT will provide infrastructures, services, tools and applications that will support the development of smart cities by optimizing the use of cloud computing to overcome some of the current challenges and limitations of the Intenet of Thing (IoT). Prototypes of the ClouT solution will be deployed in four cities: Santander (Spain), Genoa ( Italy), and Mitaka and Fujisawa (Japan). Each prototype city will develop innovative applications useful in domains such as security, transport, healthcare, and entertainment.