In natural languages, personal nouns (e.g., madame, ministre) are used very frequently and it is usually not very difficult to identify and interpret them in texts. If one tries to define them more precisely, however, one is confronted with a series of challenges. This contribution gives an overview of several types of difficulties that can be observed when trying to establish distinctions between personal nouns and other words. They are related to lexical differences between (personal) nouns and (personal) names, the referential boundaries of humanness, some morphological and semantic properties of French personal names, their syntactic behavior as personal nouns in French as well as the types of predications that may be used in order to distinguish between personal noun use and other uses.