Current trends towards automatic network management have lead to the definition of policies providing a better control on today's Internet domains. These domains can be composed of more than one access network each with its capabilities, devices, users and a specific behavior defined by policies. Thus, policies are defined to control service provisioning and automate network resource configuration. However, being aware of all the changes occurring in these domains is a difficult task. The difference in the quality of services provided by different pervasive environments and the growth in the mobility nature of users, and the heterogeneity of access networks lead to the problem of providing services adapted to users' needs and context. In this paper, we present a policy-driven approach to control the nomadicity of users and provide them services in agent-based pervasive environments. The agents achieve distributed tasks like gathering relevant context information in order to build up profiles helping adapt the requested service. Policies are applied to network devices and agents to control their behaviors. New policies are created automatically after a negotiation process between the user and the network in order to handle the events occurring in the surroundings. This framework helps tailoring services and policies according to the new environment's information while respecting a limited delay and a good scalability.