As “smart cities” or “eco cities” proliferate, innovation has become a central component of urban policy. This chapter discusses the politics of innovation in urban contexts by focusing on city experiment, that is, experiments conducted in the city and with the city. The analysis of city experiments is a path for displacing oppositions between (1) the stability of urban space and the “disruption” introduced by innovation, (2) “technical” innovation and “social” innovation, (3) the local life of cities and the global flows of technologies and capital. Instead, one can contrast various propositions for organizing innovation in the city. The example of innovation policy in San Francisco and its associated controversies shows that these propositions offer various imaginations of the beneficiaries of innovation, and eventually different understandings of urban democracy. In particular, the imagination of the city as a place for real-time experiments and the increasing role of global investment can be contrasted with other propositions, which make collective life the means and ends of urban innovation.