Résumé
We propose in this paper an extension of Conceptual Graphs that allows to use datatypes (strings, numbers, ...) for typing concept nodes. Though the model-theoretic semantics of these datatypes is inspired by the work done for RDF/RDFS, keeping sound and complete projection-based algorithms for deduction has led to strong syntactic restrictions (datatyped concept nodes of a target graph cannot be generic). This restriction, however, allows us to smoothly upgrade our extension to rules, and to introduce functional relations (that compute the value of datatyped concept nodes) while keeping sound and complete reasonings.