This article contributes to current historical knowledge on the relationship between Crown and local municipal power in Old Regime France. In particular, it examines the political language of bien public mobilized by Marseillais elites and royal administrators between 1660 and 1700 in the context of French commercial expansion. Traditionally, ‘public good’ could be understood in two distinct ways. Derived from royal absolutist doctrine, public good was what the king willed to preserve the state, a collection of diverse, corporate bodies held together by royal justice and reason. Derived from civic humanistic, municipal traditions, public good was the united will of the civic community. Investigating three moments where these two definitions of public good converged and collided – during Marseille's urban expansion (1666), in the local justification of modern commerce, and in the deliberations at the Council of Commerce (1700) – this article points to several mutations in the language of public good at the end of the seventeenth century. Pointing to the convergence of civic humanistic and absolutist traditions, this article demonstrates that centralization under Louis XIV, rather than obscuring local traditions, allowed for the intensification of civic humanistic, republican sensibilities.