International audience Introduction & Goals. The acquisition of L2 Prosody (intonation, accentuation, rhythm, etc.) and L2 segmentals (consonants and vowels) has mainly been studied separately. Most L2 phonology models such as [1] or [4] do not make clear predictions concerning the acquisition of segmentals via their interface with the prosodic structure. Yet, some studies report effects of the L1 prosodic hierarchy in the production of L2 English consonants (e.g., [3]). To the best of our knowledge, no research has studied whether prosody (via the production of accented syllables or boundary tones) has a positive/negative/null effect on L2 French vowels' accuracy. [2] claims that the production of accented syllables or final melodic contours (rising or falling) has positive effects for better perceiving and producing certain L2 French vowels. For instance, this author assumes that French vowel /y/ is better perceived and produced by L2 learners when it occurs in strong prosodic positions (when final rising/high pitch movements at the right boundaries of Accentual Phrases (AP) or rising final contours in yes-no neutral questions/major continuations are produced). However, no experimental research has been conducted in order to validate these pedagogical assumptions. In this paper, we focus on the production of L2 French rounded vs unrounded oral vowels