In addition to the phrase-final accent (FA), the French phonological system includes a phonetically distinct Initial Accent (IA). The present study tested two proposals: that IA marks the onset of phonological phrases, and that it has an independent rhythmic function. Eight adult native speakers of French were instructed to read syntactically ambiguous French sentences (e.g., Les gants et les bas lisses 'the smooth gloves and stockings') in a way that disambiguated the scope of the adjective. When the final adjective (lisses) applies to the conjoined NP, a prosodic boundary is warranted immediately before the adjective; when it applies to the second NP alone, a boundary before that NP is more appropriate. Length of the second noun and the adjective were varied from one to four syllables to investigate length-related tendencies toward phonological boundary marking and toward rhythmic placement of IA. For the materials from six speakers whose readings were correctly interpreted by native listeners, incidence of word-initial prosodic peaks was affected by both structure and length, with most reliable occurrence at onsets of Minor/Phonological Phrases. The only effect of rhythmicity independent of phrase structure was omission of FA in stress clash with IA.