European cities struggle to regulate platform-mediated short-term rental services in response to local concerns over uncontrolled tourism and affordable housing. In their efforts to tame online platforms and local hosts, cities have consistently pointed to EU law as an obstacle to effective regulation and enforcement and called for solutions at EU level. To date, research has paid limited attention to the precise role of EU law in the regulatory responses to the growth of short-term renting. This article therefore offers an explanation of how EU internal market law structures the multi-level dynamics behind short-rental regulation. Methodologically, the article relies on a contextual analysis of the EU’s legal framework for (electronic) services and an in-depth, longitudinal case study of the City of Amsterdam’s efforts to regulate its Airbnb-driven short-term rental market (2013–2023). Comprehensive empirical evidence indicates that European e-commerce law can deter governments from enforcing platform cooperation in the upstream market and, instead, prompt them to shift the burden of regulation and compliance to the ‘actual’ service providers (the hosts) in the downstream market. These upstream/downstream dynamics also help to explain the successful adoption and normative content of the recent Short-Term Rental Regulation. With its focus on the power struggle between cities and platform actors in the EU internal market, the article also offers a unique, empirically grounded account of how EU law structures urban conflicts over housing and tourism in the context of platformisation and how platformisation might affect the dynamics of European market integration more generally.