This study proposes to lead a reflection on the exploitation of the song in FLE class and its effectiveness. We find that the song as an authentic document plays an indispensable role in learning, which prompted us to develop current research to prove its importance. In this study, we first deal with the notion of the song and its historical overview in FLE class, also the musical genres of the song. Then, we treat the initiation of the exploitation of the song in the courses of FLE, in this perspective, we explain the theory of Emmanuelle Rassart, a language teacher at the Catholic University of Louvain, whose approach was inspired by CAVILAM's recommendations. It is about the exploitation of the song in the class of FLE. This theory proposes a three-phases: discovery, understanding, and expression. In the end, this study explains the various advantages of the use of the song in the class of FLE, for the teachers the song is one of the most appropriate supports, it has a great advantage on the cognitive level, memorization, motivation, culture, grammar, pronunciation, etc.