In this paper, we discuss two distinct data sets. The first comes from the allophonic process of closed-syllable laxing in Québec French, which targets final (stressed) vowels even though these vowels should in theory be syllabified in open syllables in lexical representations (e.g. lune [Öly.n(6)]; *[Öly.n(6)]). The second is found in the forms produced by a first language learner of European French, who displays an asymmetry in her production of CVC versus CVCV target (adult) forms. The former displays full preservation (with concomitant manner harmony) of both consonants (e.g. passe --> [Öpat]). The latter undergoes deletion of the initial syllable if the consonants are not manner-harmonic in the input (e.g. appétit --> [piÖti] versus tennis --> [Öni]). We argue that both patterns can be explained in an approach that draws a formal distinction between phonological representation and phonetic implementation.