The last four years have seen the rise of a movement on the French radical left positing a fundamental conflict between economic growth and ecological sustainability and calling for a reversal of growth (décroissance) against the current consensus around the concept of sustainable development. This challenge to the growth imperative and, more widely, of the ideology of progress, represents a return to the explicitly antiproductivist approaches that emerged in the early 1970s with the rise of radical political ecology. This article charts the birth of the décroissance movement, which is comprised of two components: anticonsumerist and antidevelopment. It also contrasts the movement with other closely-related ideological elements of the French antiglobalization and anticapitalist movements, elements that belong to the dominant, mainly Marxist tradition, whose anticapitalist struggle builds on the legacy of the Enlightenment period. The article concludes that, by placing antieconomicist and antiutilitarian thought drawn from social sciences on the agenda of the French radical Left, the décroissance movement could potentially generate a major paradigm shift founded on a critical evaluation of the heritage of modernity.