This article studies how to extend the concept of active objects into a structure of agents. It first discusses the requirements for autonomous agents that are not covered by simple active objects. The authors then propose the extension of the single behavior of an active object into a set of behaviors with a meta-behavior scheduling their activities. To make a concrete proposal based on these ideas, the authors describe how they extended a framework of active objects, named Actalk, into a generic multi-agent platform, named DIMA. They discuss how this extension has been implemented and report on one application of DIMA to simulate economic models.