Abstract: Communication system for monitoring traceability between at least one upstream operator (2) and at least one downstream operator (3), by way of a controller (4), using a multiplicity (CPUC1, CPUC2, CPUCn) of identification codes (CPUC), each comprising an identifier (IDU1, IDU2, IDUn) associated with a multiplicity (141, 142, 14n) of objects (14) by way of a support (15), the downstream operator (3) having a reader (17, 27) and the controller having under its control a server (9) being devised so as to accomplish the following functions: declaration of identification of any downstream operator (3), association (ASSOC1) of this identification code (CPUC) read and of the downstream operator (3) that performed the read, and recording of this association (ASSOC1) in a database (19, 35), accessible to the upstream operator (2).