With the aim of building a Corporate Semantic Web, the content of the documents must be explicitly represented through metadata in order to enable contents-guided search. The Corese engine is dedicated to the querying of corporate semantic webs whose documents are described into RDF annotations. Corese interprets these RDF metadata in the Conceptual Graphs (CG) model in order to exploit the inference capabilities of this formalism. This paper presents our mapping of RDF into CG and its interest in the context of a Corporate Semantic Web.