International audienceFollowing a study of the conversational treatment of idiomatic expressions of German talk shows, the present treaty examines in which form and in which way idiomatic expressions are being employed and treated by participants in authentic conversations. Based on four conversational corpora from various domains seven different types of auto- and hetero-rephrasals and paraphrases are described. For each type general and specific functions are then analyzed. The article also deals with idiomatic expressions which remain untreated, i. e. where no subsequent activity might provide a clue as to the understanding of the idiom in question.L'article étudie formes et fonctions de traitement conversationnel d'expressions idiomatiq...