The goal of the present paper is to study interference between French and English prosody. In order to study the influence of the prosody on the second language pronunciation, F0 slopes and vowel durations of the last syllables of prosodic groups were measured and analyzed in the pronunciation of French native speakers speaking French and English, and of English native speakers speaking English. Significant differences appear in our data between the use of F0 slopes by French speakers speaking English and the use of F0 slopes by English native speakers: most of the time, nonnative English production of F0 slopes is closer to French prosody than to English native prosody. For non-native (French speakers) vowel duration values are generally different from vowel durations in French data. However, they are somehow closer to values produced by English native speakers.