This dissertation sheds light on the symbiotic relationship that klezmer music and urban Jewish festivals have developed in contemporary Europe. It contributes to the ethnomusicological literature by showing how Jewish festivals have become privileged platforms for the dissemination of klezmer within and beyond Jewish communities. At the turn of the twenty-first century, the klezmer revival transitioned into a klezmer boom. Klezmer music, commonly and originally defined as the instrumental folklore of Eastern European Yiddish speaking communities, suddenly became more visible and popular, among Jews and non-Jews alike. Musical innovations and hybridities, the American klezmer movement, as well as the emergence of Yiddish pedagogical institutions all facilitated this European klezmer boom. However, one key aspect of this phenomenon has remained overlooked. Indeed, starting in the 1990s, Jewish culture and music festivals have mushroomed throughout urban Europe. The central hypothesis of this dissertation is that the klezmer boom and the growth of urban Jewish festivals are deeply intertwined. Drawing on urban ethnomusicology, festival scholarship, musical geography, and mapping practices, I examine the spaces and places of klezmer music in its festivalized settings. I focus on the Jazz’n Klezmer festival in Paris as my major case study. In a later dialogue, I investigate other Jewish festivals through which I challenge my hypothesis while fostering a translocal, transnational, pan-European, and transatlantic perspective. This research ultimately reveals how Jewish festivals, by developing specific territorial strategies within the ethos of their host cities, have been instrumental in the European klezmer boom.