This article shows how the recent rise of the smart city approach is actually rooted in a long history of the relations between cities and information systems. This history begins at the end of the 19th century, with the development of information-based societies. It continues during the period of cybernetics and systems theory which proved to be especially influential from the 1950s to the early 1970s. The issues raised by the smart city approach are discussed in the last part of the article. At each of these stages, doctrines and urban practices evolve in direct relation with the issue of the city as a set of information systems.