The aim of this article is to describe a database of diphone positional frequencies in French. More specifically, we provide frequencies for word-initial, word-internal, and word-final diphones of all words extracted from a subtitle corpus of 50 million words that come from movie and TV series dialogue. We also provide intra- and intersyllable diphone frequencies, as well as interword diphone frequencies. To our knowledge, no other such tool is available to psycholinguists for the study of French sequential probabilities. This database and its new indicators should help researchers conducting new studies on speech segmentation.