From the study of the time synchronization service in Paris in the 1870s, this article proposes a sociohistory of municipal public action. In order to better understand the genesis of this new public service, the article begins by reviewing the increase of time needs and the diversity of Parisian public clocks in this period. The second part is dedicated to the crucial role of the astronomers of the Observatoire de Paris regarding time standardization and in the establishment of the public time service. The last part of this article focuses on the arrangements for the exercise of a municipal governance of public clocks by studying the relations between municipal councillors, the Direction des travaux, and a private company, La Compagnie générale des horloges pneumatiques. This company marketed a clock synchronization technique that competed with the public time service. The hesitations of the municipal councillors and the city’s technical services between two synchronization techniques, electric and pneumatic, and between a marked control or a simple monitoring of the Compagnie are proof of an innovative municipal action that had difficulties defining its goals and means in a technical domain.