In this paper, we focus on the relations between prosody and grammar in Old French. For that purpose, we studied the interactions between prosodic boundaries (which can be found through versification) and syntactic boundaries, especially in the construction of paratactic subordinate clauses. Thereby, we show that the prosodic unit can be an indication of syntactic integration. However, even if it is a fact that there is some symmetry between the prosodic and syntactic boundaries, we show that prosody does not encode syntax in Old French, because prosodic boundaries can correspond to different types of syntactic boundaries.