Although translation has played a central role in language teaching for centuries, it fell out of use in the 20th century when other teaching methods were introduced and suffers now from a somewhat « bad reputation ». Since the beginning of the 21st century, however, significant research has reconsidered the usefulness of translation in the teaching and learning of languages. It has been found out that language learners very often turn to translation as a learning strategy (Naiman, 1996). The following study was conducted in a university advance writing course (CEFRL levels B2/C1). It explores whether translation can indeed be an effective tool to help language learners improve their competence in L2, especially in terms of word choice and syntax, through an experimental activity referred to here as « double translation ». Learners were then surveyed to find out about their opinions and perceptions on the use of L1 when learning a second language.