We deal with compound tenses in French, from the point of view of the past participle. We address the issue in the field of diathesis. We propose a unitary analysis of the past participle, as a marker of inaccusativity (in a broad sense), integrating its uses in compound tenses. Consequently, the auxiliary avoir, in addition to its role on the aspectual-temporal level, also plays a role as a diathesis operator. We conclude that it is possible to propose a compositional semantic analysis of compound tenses based on the meaning of the auxiliary and the meaning of the past participle.