We present in this paper a formal framework for argumentation- based dialogues between agents. These latter manage the dialogues with the help of three components: an argumentative component to generate arguments, a social component to interprete arguments, and a conventional component to manage the sequence of coherent moves. We formalize the notion of dialogue-game to address the gap between individual moves and the extended sequence of coherent moves that arise between agents. The moves are not associated with an intention, however the dialogues have a goal.