Managing and sharing RDF triples in a distributed environment is one of the important issues for realizing semantic information retrieval in the Internet. Especially, the notion of RDF classes plays an important role in semantic information retrieval. In this paper, we propose a peer-to-peer information sharing method for RDF triples based on RDF class hierarchy. In the proposed method, a class ID is assigned to each RDF class so that it can represent inclusion relations of the class hierarchy. Then, each RDF triple is given a two-dimensional key that represents the classes of the subject and the object. By using Z-order of those two-dimensional keys, peers join an overlay network based on the Multi-Key Skip Graphs. Class-based retrieval of RDF triples is then realized by a range search on the overlay network. We show that the proposed method can process class-based RDF queries efficiently.