This paper seeks to recover the foundations in order to reflect the ties (today somehow distended) between sensations / perceptions and politics. It will be tried by renewing the long debate about common sense, as a principle of intersubjective constitution of sensory experience. In this framework, urban ambiances provide a particularly relevant field of experimentation: 1/ in order to certify ties between politics and sensations; 2/ for the sort of politics they indirectly occasion, namely a kind of conservatism; 3/ and finally in order to test some potential interventions on urban ambiances and their consequences.