This study investigates stress processing through the Event-Related brain Potential (ERP) technique. It aims at evaluating whether French listeners can perceive and discriminate the Initial Accent (IA) and whether IA is encoded in the phonological representation. Participants listened to trisyllabic words in two stress-pattern conditions, with (+IA) or without (-IA) initial accenting, in an oddball paradigm. The EEG was recorded in both a passive and an active listening task, and in two different oddball versions: one where standard stimuli were +IA words and deviants -IA words, and the reverse for the other version (-IA standard, +IA deviant). Behavioral results show faster processing and less errors for +IA stimuli. ERP results show larger MisMatch Negativity component for -IA words, pointing out 1) that French listeners are sensitive to f0 manipulation, and 2) that +IA is the preferred stress template in French. Altogether, our results indicate that French listeners not only discriminate stress patterns but that IA is encoded in long-term memory, hence phonologically relevant.