The expansion of the Internet of Things (IoT) is linked with the development of Smart Cities. As sensors are becoming cheaper and more powerful, networks of smart objects are becoming wider than ever. The scope of applications of IoT in Smart Cities is huge. Smart Buildings have a huge role to play in this transformation . This revolution is socio-technical, as it involves the relation between building occupants and its technology. In this paper, we present the benefits of Multi-Agent Systems (MAS) applied to Smart Buildings. First, we study the evolution of the Smart Buildings concept from fully autonomous entities without human action, to a more people-centric approach with human feedback, highlighting the increasing levels of complexity.Based on a review of the scientific literature, we discuss how the multi-agent paradigm can offer innovative solutions to cope with this complexity. We then conclude with some perspectives and issues that still need to be addressed.