This paper presents a model for distributed applications with real-time constraints in an heterogeneous context. The proposed model is based on CORBA standard architecture, and uses the reflective object paradigm which provides the separation of concerns : functionality and management. Consequently, the model has two levels : a base-level which deals with system functionality and a meta-level with scheduling, time and synchronization constraints, as well as exception handling. These features are merged in the client/server architecture as defined in the CORBA standard. A timeout value is specified for each client object and a deadline for the server object. These time constraints allow to treat according to a "best-effort" policy the satisfaction of time specifications. After the presentation of the main features of the proposed model, a short example based on the display of a multimedia document is described.