Non-therapeutic cosmetic use of at least one compound capable of modulating the interaction between a first and a second partner proteins, homologs or fragments of said proteins, said first and second proteins being Skin Aspartic Protease or SASPase, and Filaggrin-2 or FLG2 as active agent for treating and/or preventing an esthetic defect of the skin and/or its integuments related to an imbalance in epidermal cell differentiation and/or proliferation, said compound being represented by the following general formulas (Ia) or (Ib): wherein: - R 1 is H, a linear or branched, saturated or unsaturated C 1 -C 4 alkyl, or -C R 8 where R 8 is a linear or branched, saturated or unsaturated C 1 -C 4 alkyl, R 1 preferably being H, a methyl, ethyl, propyl, or -C R 8 where R 8 is a methyl, ethyl or propyl; - R 2 is =O, -OR 9 or -OC R 9, where R 9 is H or a saturated C 1 -C 2 alkyl, R 2 preferably being =O or -OR 9, preferably =0; - R 3, R 4, R 5, R 6, R 7 are each independently H; -NO 2; -OH; a fluorine; -CF 3; a linear or branched, saturated or unsaturated C 1 -C 4 alkyl; a phenyl; -OC -CH(Ph) 2; -O-Ph-X with X representing H, -OH, -NO 2, a fluorine, a linear or branched, saturated or unsaturated C 1 -C 4 alkyl or alkoxy; -O-S(O 2)-Ph-Z with Z representing a linear or branched, saturated or unsaturated C 1 -C 4 alkyl; -R 8 OH; -OR 9; -OC R 9 with R 8 and R 9 being as defined previously; -R 10 Ph with R 10 being a linear or branched, saturated or unsaturated C 1 -C 4 alkylene; or -OC -Y n -Ar 1 - m with - n being 0 or 1 and m being an integer ranging from 0 to 4, providing that n and m are not simultaneously 0, Y representing a linear or branched, saturated or unsaturated C 1 -C 4 alkylene, X being as defined previously, and Ar 1 being or with * being a bond with Y and @ is a bond with X and the physiologically acceptable salts thereof, the homologs displaying a sequence having at least 85 % identity with one of the partner proteins and having biological activity of same nature, the fragments being portions of a partner protein comprising from 6 to 260 contiguous amino acids and having biological activity of same nature. - R 1 is H, a linear or branched, saturated or unsaturated C 1 -C 4 alkyl, or -C R 8 where R 8 is a linear or branched, saturated or unsaturated C 1 -C 4 alkyl, R 1 preferably being H, a methyl, ethyl, propyl, or -C R 8 where R 8 is a methyl, ethyl or propyl; - R 2 is =O, -OR 9 or -OC R 9, where R 9 is H or a saturated C 1 -C 2 alkyl, R 2 preferably being =O or -OR 9, preferably =0; - R 3, R 4, R 5, R 6, R 7 are each independently H; -NO 2; -OH; a fluorine; -CF 3; a linear or branched, saturated or unsaturated C 1 -C 4 alkyl; a phenyl; -OC -CH(Ph) 2; -O-Ph-X with X representing H, -OH, -NO 2, a fluorine, a linear or branched, saturated or unsaturated C 1 -C 4 alkyl or alkoxy; -O-S(O 2)-Ph-Z with Z representing a linear or branched, saturated or unsaturated C 1 -C 4 alkyl; -R 8 OH; -OR 9; -OC R 9 with R 8 and R 9 being as defined previously; -R 10 Ph with R 10 being a linear or branched, saturated or unsaturated C 1 -C 4 alkylene; or -OC -Y n -Ar 1 - m with - n being 0 or 1 and m being an integer ranging from 0 to 4, providing that n and m are not simultaneously 0, Y representing a linear or branched, saturated or unsaturated C 1 -C 4 alkylene, X being as defined previously, and Ar 1 being or with * being a bond with Y and @ is a bond with X and the physiologically acceptable salts thereof, the homologs displaying a sequence having at least 85 % identity with one of the partner proteins and having biological activity of same nature, the fragments being portions of a partner protein comprising from 6 to 260 contiguous amino acids and having biological activity of same nature.