Published in 1770, Le cosmopolisme by Joseph Honoré Rémy is the first pamphlet in French to elaborate upon a political philosophy of cosmopolitanism. I first present a biography of Rémy with original elements concerning his membership of the Freemasonic Lodge of the Nine Sisters. This article analyses his pamphlet and argues that his cosmopolitanism is a way of transcending the public and the private. Such transcendence is, I argue, achieved in two ways: first, through the authorial function of writing as a ‘cosmopolite’ and second, through an understanding of cosmopolitanism as a human fraternity inspiring private and public virtues in republican monarchies.