This method comprises the following steps of applying a watermarking function to motion vectors calculated by estimation of movement between images of a video signal, followed by a step of generating the watermarked video signal by compensating movement with the aid of the watermarked motion vectors. The watermarking function is applied by marking the coordinates of the selected motion vector in a reference space, certain portions of this space constituting a first zone and the other portions of this space constituting a second zone complementary to the first, assigning a binary value to each of the two zones, and, if necessary, modifying the coordinates of the selected motion vector so that it is in the zone whose binary value corresponds to a bit of a marking key associated with the selected motion vector.