More and more home devices are equipped with advanced computational capabilities to improve the user satisfaction (e.g., programmable heating system, Internet TV). Although these devices exhibit communication capabilities, their integration into a larger home monitoring system remains a challenging task, partly due to the strong heterogeneity of technologies and protocols. In this paper, we therefore propose to reconsider the architecture of home monitoring systems by focusing on data and events that are produced and triggered by home devices. In particular, our middleware platform, named DIGIHOME, applies i) the REST (REpresentational State Transfer) architectural style to leverage on the integration of multi-scale systems-of-systems (from Wireless Sensor Networks to the Internet) and ii) a CEP (Complex Event Processing) engine to collect information from heterogeneous sources and detect application-specific situations. The benefits of the DIGIHOME platform are demonstrated on smart home scenarios covering home automation, emergency detection, and energy saving situations.