Abstract Second language interactional competence has for long remained out of the focal concerns of research on second language acquisition (SLA). Over the past two decades, however, the field has seen emerge a prominent line of conversation-analytic (CA) SLA research investigating the procedures and resources L2 speakers use to accomplish actions in interaction and coordinate these with others, and how these procedures change over time and proficiency levels. This chapter discusses the key role played by research on French in these developments in terms of the advancement of methods for longitudinal investigations of L2 interactions, the conceptualization of L2 interactional competence and — relatedly — L2 grammar-for-interaction, and the identification of the basic developmental trajectory of such competence. It presents the cumulative evidence stemming from developmental studies of L2 interactional competence and identifies existing French L2 corpora suitable for such studies. The chapter closes with a discussion of the methodological limits of current research as well as avenues for future investigations.