In response to ecological and economic objectives, many cities are now implementing measures to reduce or completely switch off public lighting at night. While these policies support the energy transition, they also raise significant social concerns. Research has shown for decades that public space and mobility are gendered, revealing ongoing inequalities in access and use between women and men. This study investigates how public lighting shutdowns affect nighttime mobility and safety perceptions, with specific attention to gender dimensions. Public lighting serves beyond its technical function as a symbolic indicator of informal surveillance. When reduced or eliminated, it can transform spatial practices and deepen existing social and gender inequalities in urban space access. This research examines the case of Yverdon-les-Bains, a municipality that recently implemented partial nighttime lighting shutdowns and surveyed residents about their acceptance (385 respondents). This fieldwork allows analysis of how a local lighting policy, driven by environmental goals, affects perceptions of insecurity, nighttime mobility patterns, and gender inequalities. The findings will be compared with a broader analysis of the Lake Geneva region to determine whether the observed effects stem directly from public lighting shutdowns or from a more general unequal distribution of insecurity perceptions. This research aims to document both the social impacts of these lighting policies and, more broadly, to illuminate how perceptions of insecurity practically affect nighttime mobility patterns.