Increasing paper strength by surface treatment

This method for treating the surface of paper and/or one of the layers thereof, comprises the following successive steps:i) Supplying an aqueous suspension S of polysaccharide;ii) Supplying an aqueous dispersion D comprising (a) particles of at least one anionic water-swellable polymer P and (b) at least one compound selected from a mineral salt, an organic salt, an organic dispersing polymer and the mixtures thereof;iii) Mixing the suspension S and the dispersion D to obtain a mixture M;iv) Applying the mixture M to the surface of the paper and/or to at least one of the layers thereof.