This study aims at describing past participle agreement rules in the Romance languages. These are mainly considered as being an arbitrary set of rules; however, this study is based on the hypothesis that this kind of agreement has primarily a pragmatic function. Indeed, based on the hypothesis that past participle agreement is an example of verb-argument agreement, such as the subject-verb one, we will demonstrate that this agreement is triggered by a subject or a direct object with topic function. The pragmatic factor will be then integrated with those traditionally recognised in the literature, namely nuclear syntactic functions and the auxiliary selected. Finally, we will show why such a variation exists in the Romance languages.