International audienceOur paper explains the birth of an environmental problem, i.e. light pollution, viewed as a socio-technical controversy. Supported by the actor-network approach, it traces over forty years the conditions of its emergence, transformation and dissemination to local, national and transnational levels and through various professional disciplines. Schematically, “environmentalists” uphold a holistic approach of “nocturnality” and define artificial light as a pollutant. Facing them, the “technicist” defends a segmented approach and defines artificial light as a nuisance. The introduction of this controversy into the political agenda leads to institutional decisions that grasp with difficulty all its social, scientific and sp...