Many studies agree in considering that the introduction of referents in a text operates by very specific linguistic means, in particular indefinite NPs. Other work on corpus slightly modifies this assertion, but few of them focus on contemporary French. Therefore, using the DEMOCRAT corpus, our objective is to observe real data. Using parts of texts of the 20th century, we will carry out a precise inventory of 960 “first mentions”. We study texts of various genres to identify the grammatical categories used and their proportion. On the basis of both a quantitative and qualitative analysis, we thus show, firstly, that the indefinite NPs, are note many as predicted, secondly, that the categories used in the “first mentions” largely depend on the genres of discourse and the referent ontological status, a parameter ignored in most of the previous works mentioned in this paper.