We present an advanced multimedia infrastructure that integrates continuous real-time media streams within the WWW. This new service architecture focuses on advanced facilities for dealing with multimedia contents. A mediation server is at the heart of the infrastructure. It organizes and structures the multimedia information space. In addition to simple services for accessing and delivering multimedia data, it provides new functionalities for filtering and querying multimedia content. Content servers and on-line sources deliver media streams integrated within synchronized multimedia presentations. We think that the infrastructure will offer new opportunities for WWW-based information systems and electronic commerce.