In this paper, we propose a new method to realize quick update of information concerned with shared contents in Peer-to-Peer (P2P) networks. The proposed method is a combination of a hierarchical P2P architecture and a tag-based file management scheme. The hierarchical architecture consists of three layers: the top layer consisting of a collection of central servers, the middle layer consisting of a set of sub-servers, and the bottom layer consisting of a number of user peers. Indexes of files held by each user peer are stored at the sub-servers in the middle layer, and the correlation between file indexes and sub-servers is maintained by central servers using tags. We implemented a prototype of the proposed method using Java, and evaluated the performance through simulations using PeerSim 1.0.4. The results of our experiments indicate that the proposed method is a good candidate for “real-time search engines” in P2P systems; e.g., it completes an upload of 10, 000 file indexes to the relevant sub-servers in a few minutes and achieves query forwarding to relevant peers within 100ms.