Jean-Loup Kastler is a historian, an associate researcher at the Institute of Geography and Sustainability of the University of Lausanne and at the Institute of Modern and Contemporary History of the University of Paris 1 Panthéon-Sorbonne. He is also a history and geography teacher and the coordinator of the international sections at the Lycée international de Ferney-Voltaire.
Holding a PhD in early modern history since December 2025, he devoted his doctoral dissertation to the social, political, and environmental origins of the French Revolution in the mountainous areas lying between Geneva, Versoix, Grenoble, and the Dauphiné. Entitled The Metamorphoses of the Ideal City in Mountain Country (1768–1788): From the Philosophical Utopia of Versoix to the Moral Ecology of the Crowd of the Day of the Tiles, this research examines the shift from a bourgeois, enlightened urban ideal, conceived by reforming elites, to a popular uprising grounded in the defence of the commons and of the material conditions of existence.
His work lies at the intersection of social history, environmental history, political history, and historical geography. It investigates the ways in which territories, natural resources, collective rights, and local institutions contribute to the formation of political ideas and practices.