The aim of this paper is to investigate prosodic phrasing and more precisely the use of prosodic cues in the marking of morphosyntactic units in French. As a first step towards this goal, a perception study was conducted on 27 listeners, who had to perform 3 distinct perceptual tasks on 32 syntactically controlled phrases read by a female speaker: a prominence strength judgment task, a boundary strength judgment task, and a task where listeners had to choose between 4 different phrase groupings intended to reflect the potential choices of prosodic phrasing. The corpus consists of syntactically ambiguous structures manipulating high and low adjective attachment on 2 coordinated nouns. It was designed to specifically test the role of prominence and boundary cues in the marking of prosodic constituency. Our results show that listeners use prosodic cues to discriminate between the two syntactic structures, with boundary cues being more readily used to capture morphosyntactic structuring. More interestingly, our results indicate that prominence and boundary cues are used to distinguish finer-grained grouping levels than those predicted by traditional descriptions on French prosodic structure.