Today, numerous studies explore the concepts of Smart City and City Information Modeling (CIM), highlighting the need to develop methods for systematizing, analyzing, and representing data typically managed by different information systems. The shared vision is to integrate BIM outputs with those from GIS, as well as with data from various other sources (historical documents, technical reports, IoT sensors, etc.), within a single working environment, thus building a true digital twin of extensive territorial areas. The goal is to optimize decision-making processes at both building and urban scales, and a potential solution lies in the combined use of Business Intelligence (BI) tools, which allow for the reading, integration, and querying of data stored across the different information systems mentioned. In this context, the present contribution aims to frame the issue of data integration and to test a digital solution integrating BIM, GIS, and BI, developed through a collaboration between the research group at the University of Naples Federico II and the company ACCA Software, and applied to publicly owned building assets.