This study adopts a case study approach to investigate the impacts of synchronous computer-mediated communication (CMC) learning environments on learners' perception of social presence. The participants were twelve French as a foreign language (FFL) beginners in a Taiwanese university. Divided into three groups, they conducted some tasks in three different learning environments (video/audio, audio and face-to-face) during an academic semester. Before each oral task, all the participants had to conduct the same task in synchronous text chat. The participants' interview transcriptions, learning journals and the instructor's observation journal provided information about the impacts of each environment on their perception of social presence. The results of the study suggested that the differences in the environments are reflected in the learners' perception of social presence.