The advancement of renewable energy and low carbon technologies, such as electric vehicles, necessitates that smart buildings adopt innovative energy use cases to become adaptive and responsive. Additionally, the proliferation of Internet of Things (IoT) devices introduces new applications for enhancing comfort, air quality, health, and energy consumption. These evolutions require Building Automation Systems (BAS) to manage new devices and implement novel applications, which are often beyond the capabilities of current BAS technologies. Consequently, this paper proposes a Cyber-Physical Architecture that facilitates the integration of third-party IoT devices and the development of novel use cases. Specifically, the architecture supports the implementation of a Smart Energy Management System alongside standard BAS to optimize energy usage in smart buildings through IoT and artificial intelligence algorithms. The paper also presents a case study of the architecture’s implementation in a smart building in Nice, France, and discusses the advantages and disadvantages of the proposed cyber-physical architecture for smart energy buildings.