This thesis offers an empirical assessment of the strength of cross-side externalities on the home-sharing platform Airbnb. Whereas much of the existing literature treats digital platforms as global and delocalized marketplaces, this study investigates whether network effects vary across space. Because Airbnb’s services are delivered in specific physical locations, the platform effectively operates through multiple geographically bounded sub-markets. This work therefore evaluates Airbnb through the lens of a spatially localized digital platform. The findings indicate that differences in local market conditions and industry structures give rise to distinct patterns of network effects across sub-markets. To examine these mechanisms, the study focuses on the region of Nouvelle-Aquitaine (France), a context that makes it possible to estimate the magnitude of cross-side externalities by leveraging two concurrent shocks affecting both supply and demand.