The concepts of smart city and sharing economy are at the centre of a number of current debates, which touch upon, among others, issues like the current urbanisation trends, the particular economic situation we are facing in the last years, the spread of connectivity and of new technologies and the innovation process in general. This working paper looks at the different and common characteristics of both smart cities and sharing economy models, in order to explore their interaction and complementary dynamics. This is done by analysing the specific features of the two, as well as at regulatory and competition issues they trigger within our current legal framework. The final aim is to make some policy suggestions to the local governments, which are called to cope with these phenomena, and for which the latter could constitute a great opportunity to enhance the local welfare.