To a backdrop of dizzying urbanization, French utopian thinkers of the nineteenth century set out to explore the transformative possibilities of the modern metropolis. Linking literary analyses with diverse strands of cultural and intellectual history, this study considers how the utopian vision of the city in turn came to impinge on prose writing by poets: in Saint-Simonian literature, and in texts by Théophile Gautier, Charles Baudelaire and Arthur Rimbaud. At points steeped in the hyperbolic rhetoric of utopian projects, these texts nonetheless wear away at the internal coherence of that rhetoric and the idealizing meanings it supports. What emerges from Greg Kerr’s analysis is a hitherto unfamiliar dimension of these writings, revealing the alertness of some of the greatest exponents of nineteenth-century poetry to the dynamic possibilities of utopian writing, and suggesting new ways to understand the evolution of poetic discourse across the century.