The invention concerns a method of inserting a watermark in an image comprising at least three components, the method comprises the steps of decomposing at least one component of the image into detail sub-bands in various directions and comprising coefficients, each coefficient being characterized by its position in the detail sub-band to which it belongs and its amplitude, of determining, for each position, information representing local amplitude variations from the amplitudes of the coefficients at this position in the various detail sub-bands and the coefficients close to this position in the various detail sub-bands, of determining a watermarking strength at each position from the information representing determined local amplitude variations in the said position and inserting a watermark composed of a plurality of binary information in the image, inserting each item of binary information at a position on the image according to the watermarking strength determined for a position corresponding to the position at which the binary information is inserted.