This study compares the development of prosodic processing in French- and German-learning infants. The emergence of language-specific perception of phrase boundaries was directly tested using the same stimuli across these two languages. French-learning (Experiment 1, 2) and German-learning 6- and 8-month-olds (Experiment 3) listened to the same French noun sequences with or without major prosodic boundaries ([Loulou et Manou][et Nina]; [Loulou et Manou et Nina], respectively). The boundaries were either naturally cued (Experiment 1), or cued exclusively by pitch and duration (Experiment 2, 3). French-learning 6- and 8-month-olds both perceived the natural boundary, but neither perceived the boundary when only two cues were present. In contrast, German-learning infants develop from not perceiving the two-cue boundary at 6 months to perceiving it at 8 months, just like German-learning 8-month-olds listening to German (Wellmann, Holzgrefe, Truckenbrodt, Wartenburger, & Höhle, 2012). In a control experiment (Experiment 4), we found little difference between German and French adult listeners, suggesting that later, French listeners catch up with German listeners. Taken together, these cross-linguistic differences in the perception of identical stimuli provide direct evidence for language-specific development of prosodic boundary perception.