Terminal identification method in a system for providing multimedia content, in which: a) a terminal acquires (101, 103) then decodes (105, 107, 109) multimedia temporal content in order to generate a multimedia stream in unscrambled form comprising at least one temporal succession of time intervals clocked at a predefined frequency, the set of information bits necessary for displaying a single complete image or for playing a sound on a multimedia apparatus being transmitted during a single time interval, and each time interval corresponding to a single image or to a single sound, this multimedia stream being able to be played by a multimedia apparatus connected to this terminal, b) a terminal identification device transmits (116, 144, 103) an identification command to this terminal, characterized in that: c) in response to this command, the terminal triggers and alternately inhibits a predetermined modification of at least some of the information bits necessary for playing a sound or displaying a complete image contained in the multimedia stream in such a way as to obtain a modified multimedia stream, and transmits this modified multimedia stream as a multimedia stream to be played by the multimedia apparatus, the choice between triggering and inhibiting the predetermined modification being carried out as a function of an identifier of the terminal or of a group of terminals to which this terminal belongs, and the tenor of said predetermined modification being independent of the identifier of the terminal or of the group of terminals to which it belongs, d) the terminal identification device acquires the modified multimedia stream transmitted by the terminal and determines the identifier of the terminal or of the group of terminals to which it belongs on the basis of the transmitted command and the presence or absence, in response, of the predetermined modification in the acquired multimedia stream, and independently of the tenor of said predetermined modification. a) a terminal acquires (101, 103) then decodes (105, 107, 109) multimedia temporal content in order to generate a multimedia stream in unscrambled form comprising at least one temporal succession of time intervals clocked at a predefined frequency, the set of information bits necessary for displaying a single complete image or for playing a sound on a multimedia apparatus being transmitted during a single time interval, and each time interval corresponding to a single image or to a single sound, this multimedia stream being able to be played by a multimedia apparatus connected to this terminal, b) a terminal identification device transmits (116, 144, 103) an identification command to this terminal, c) in response to this command, the terminal triggers and alternately inhibits a predetermined modification of at least some of the information bits necessary for playing a sound or displaying a complete image contained in the multimedia stream in such a way as to obtain a modified multimedia stream, and transmits this modified multimedia stream as a multimedia stream to be played by the multimedia apparatus, the choice between triggering and inhibiting the predetermined modification being carried out as a function of an identifier of the terminal or of a group of terminals to which this terminal belongs, and the tenor of said predetermined modification being independent of the identifier of the terminal or of the group of terminals to which it belongs, d) the terminal identification device acquires the modified multimedia stream transmitted by the terminal and determines the identifier of the terminal or of the group of terminals to which it belongs on the basis of the transmitted command and the presence or absence, in response, of the predetermined modification in the acquired multimedia stream, and independently of the tenor of said predetermined modification.