This paper focuses on the contributions a computer-mediated blended course can make for learning vocabulary in French as a Foreign Language (FFL). This course included class and on-line sessions, using Computer Mediated Communication (CMC) tools (forum and chat), for a written macro-task by French-learning Cypriot students accompanied in distance learning by FFL tutors. In the first part we present difficulties in vocabulary learning as well as in written production. We also tackle two central notions for this study: the task in an action-oriented approach, and scaffolding to support the process of learning. In the second part we describe the blended learning course, the participants and the task involved. In the third part, we identify tutors' support for frequent lexical errors occurring during chat sessions and in some of the forum messages. Furthermore, we analyse traces of the tutoring activity in the final written production (which consists of a travel guide to Cyprus). We proceed by comparing the content of the guide and online interaction between learners and tutors in both synchronous (chat) and asynchronous (forum) sessions. The study shows that tutors mainly give no feedback for the most frequent lexical errors (written form and lexical units used in English instead of French), both in chat sessions and in the forum messages. We believe this might be a strategy intended to encourage students to communicate. The support provided for the use of an inappropriate lexical unit is varied in chat sessions, while no feedback has been given for this problematic point in forums. The research also reveals that effective support strategies vary, and are mostly delivered with the same CMC tool that the learner used in his/her error.