This article is based on the comparability of French and Japanese to show that certain nominal plurals are not understandable by the classical quantitative type representation, because they are actually part of a process of constructionnalisation whose we compare linguistic mechanisms in these two languages. A precise type of indefinite plurals in French as well as the nominal plurals obtained by reduplication in Japanese thus require to be redefined as constructions, bringing out a new meaning which imposes a particular enunciative context. Our contrasting analysis leads to the following two conclusions: this process is different in French (procedural constructionalization) and in Japanese (lexical constructionalization); at the interlinguistic level, the phenomenon of nominal pluralization is in this way located in a continuum between a referential pole (the plural as a content) and a non referential pole (the plural as a procedure).