In late eighteenth-century France, questions about the regulation and standardisation of measurements enthralled the intellectual and scientific elites, state administrators, large-scale traders, members of the artisanal world and of the engaged reading public. In the revolutionary period, members of these different (and fluctuating) groups formulated, influenced, and responded to a metrological reform meant to introduce a new system of standardised units suitable to all measuring activities and all places. As they contributed to shape metrication, they were simultaneously constructing the new political regime and their place within it. This dissertation considers the early history of the metric system as a testing ground to investigate how the scope and reach of both scientific expertise and state action changed in France during the revolutionary period. Through the metric reform, the authority of an esoteric approach to scientific knowledge and the power of the new state emerged interlocked. A new space opened, within the state, for the establishment of a scientific expert detached from administrative and technical concerns, a figure that was substantially different from the hybrid academician of the Old Regime. Political actors engaging with metrication were looking for a balance between the wish to acquire a better understanding of the country’s economic life and liberal notions of non-intervention and deregulation. By the end of the decade, this was coming into focus: the state was letting go of its ambitions to manage production whilst reinforcing its power to monitor productivity outcomes. Metrication led republican administrators to test the reach of state governance across space: they realised that the involvement of expert members of the public was crucial for metrication to have any hope of succeeding; they also learnt that successful standardisation required reaching a common agreement about the meaning of precision. The metric system, born as a scholarly ideal tied to antique republicanism, ended up being a system well-geared towards the mechanisation of production.