This paper analyses prosodic properties of three discourse particles (DP) in French: 'alors' ('so'), 'bon' ('well') and 'donc' ('thus'), according to their different pragmatic functions. DP occurrences of these words extracted from a large speech database have been annotated manually with pragmatic labels. For each DP, prosodic characteristics of occurrences of each pragmatic function (conclusive, introductive, etc.) are automatically extracted. Then, for each DP and each pragmatic function, the most frequent F0 forms are retained as the representative forms. Results show that a pragmatic function, common to several discourse particles, gives rise to a uniform prosodic marking, and this lead to suppose that such DPs are most of the time commutable.