The present study evaluated the effects of explicit instruction on advanced French second language (L2) learners' (n = 18) contextually appropriate use of two stylistic variables (/l/ deletion vs. retention and "ne" deletion vs. retention) using two different task types. A planned and unplanned oral task was used to assess students' productive stylistic knowledge before and after the instructional treatment. Performance on both tasks was then compared to a corpus of native French (L1) speakers (n = 12) recorded under the same conditions. As hypothesised, the findings revealed that explicit instruction triggered changes in students' productive use of the target features; however, their ability to align to L1 stylistic norms was mediated by two factors: task types and linguistic complexity of the stylistic variants. Additionally, although instruction prompted change in the use of these variables, some learners reported being unwilling to use informal features, suggesting that personal speech-style preferences may also moderate the use of specific stylistic variants and should, therefore, be further considered in research examining the development of L2 sociolinguistic competence.