The influence of development and literacy upon syllabification in French was evaluated by comparing the segmental behavior of 4- to 5-year-old preliterate children and adults using a pause insertion task. Participants were required to repeat bisyllabic words such as "fourmi" ("ant") by inserting a pause between its two syllabic components (/fur/-/mi/). In the first experiment we tested segmentation over a range of 49 double intervocalic consonant clusters. A similar general segmentation behavior was observed in both age groups, with a pattern that fit the predictions from a legality principle-based model of syllabification. Experiment 2 revealed that opacity between phonological and orthographic representations lead to increased ambisyllabic responses and a reduction in segmentation consistency in adults. In total, these findings indicate that syllabic forms are consistently represented from an early age, but that segmentation in metalinguistic tasks is susceptible to contamination from spelling and etymological knowledge.