Short-term rentals mediated by digital platforms have positive and negative impacts that are unevenly distributed among socio-economic groups and places. Detrimental impacts on the housing market and quality of life of long-term residents have been particular contentious in some cities. • In the 12 cities studied in the report (Amsterdam, Barcelona, Berlin, Brussels, Lisbon, London, Madrid, Milan, Paris, Prague, Rome and Vienna), city governments have responded differently to the growth of short-term rentals. • The emerging local regulations of short-term rentals take multiple forms and exhibit various degrees of stringency, ranging from rare cases of laissez-faire to a few cases of partial prohibition or strict quantitative control. Most city governments have sought to find a middle-ground approach that differentiates between the professional rental of whole units and the occasional rental of one’s home/ primary residence. • The regulation of short-term rentals is contentious and highly politicised. Six broad categories of interest groups and non-state actors actively participate in the debates with contrasting positions: advocates of the ‘sharing’ or ‘collaborative’ economy; corporate platforms; professional organisatons of short-term rental operators; new associations of hosts or ‘home-sharers’; the hotel and hospitality industry; and residents’ associations/citizens’ movements. • All city governments face difficulties in implementing and enforcing the regulations, due to a lack of sufficient resources and to the absence of accurate and comprehensive data on individual hosts. That data is held by corporate platforms, which have generally not accepted to release it (with a few exceptions) nor to monitor the content of their listings against local rules. • The relationships between platforms and city governments have oscillated between collaboration and conflict. Effective implementation is impossible without the cooperation of platforms. • In the context of the European Union, the debate has taken a supranational dimension, as two pieces of EU law frame the possibility — and acceptable forms — of regulation of online platforms and of short-term rentals in EU member states: the 2000 E-Commerce Directive and the 2006 Services Directive. • For regulation to be effective, the EU legal framework should be revised to ensure platform account- ability and data disclosure. This would allow city (and other ti ers of) governments to effectively enforce the regulations that they deem appropriate. • Besides, national and regional governments, who often control the legislative framework that defines particular types of short-term rentals, need to give local governments the necessary tools to be able to exercise their ‘right to regulate’ in the name of public interest objectives.