[en] In this article, we propose to reduce the distinction between clauses and sentences to the categorial feature of their heads. Sentences are defined as a projection of the tense morpheme, and non-finite clauses, as a projection of a nominal functor whose distribution obeys the Case theory. We claim further that sentences include a clause (verbal or nominal) and that tense, axiliary, agreement and negation are external to the clause. This articulation between Clauses and sentences leads to a unified analysis of the distribution of participial and nominal morphemes in independant sentences (compound tenses) and in non-finite constructions.