The document presents an overview of semantic 3D city models using CityGML for urban analytics and data integration, emphasizing the need for an integrative model that links various sector models for enhanced coherence. It outlines how city models can be decomposed into meaningful objects with defined spatial properties and discusses applications such as energy demand estimation and environmental noise simulation. The document also highlights the widespread adoption of CityGML across various cities globally and its role in supporting urban planning and analytics.