|Abstract:||In spoken French, it is often possible to hear a schwa-sound appearing in words or sequences of words in which this sound does not etymologically exist. Since comprehensive and systematic data concerning this phenomenon are lacking in the literature, this paper presents an investigation in which the examples of schwa-epenthesis that are only marginally mentioned are systematically collected and submitted to French native speakers. It is shown that the majority of these speakers almost systematically insert a schwa-sound at word boundaries to avoid the formation of complex consonant clusters in pronunciation. Arguing that this phenomenon aims at improving the syllable structure within the French 'chaÃ®ne parlÃ©e', this paper explores the morpho-phonological contexts in which schwa-epenthesis regularly occurs in French. In addition, it is suggested that schwa-epenthesis is also apparent in expressions such as 'bourses pleines', as well as in the formation of some nouns and adverbs, where an etymologically motivated e-instable appears in written language. In order to support this hypothesis, an attempt is made to analyse schwa-epenthesis in French within the frame of optimality theory. It is shown that all the discussed examples can be explained by a single epenthesis-ranking of OT's basic syllable structure constraints.