The present document specifies the requirements for an initial semantic model for the smart cities domain based on a limited set of use cases and from available existing data models. The present document has been developed in close collaboration with AIOTI@ the H2020 Large Scale Pilots and with ETSI activities in the smart cities domain. Further extensions are envisaged in the future to cover different aspects in the smart cities domain@ for example focusing in public equipment. The associated ETSI TS 103 410-4 [i.9] will define the ontology extension (i.e. the semantic model) for the smart cities domain based on the requirements and use cases specified in the present document.