The invention relates to a cosmetic assembly comprising: a) a first aqueous composition comprising: at least one active agent chosen from peroxides a hydroxy acids ß hydroxy acids and mixtures thereof and at least one polymer comprising at least one monomer containing a sulphonic group and b) a second aqueous composition comprising: an anionic foaming surfactant and an amphoteric foaming surfactant in an amphoteric surfactant/anionic surfactant ratio ranging from 0.9 to 80/20 the total content of anionic and amphoteric surfactants being greater than or equal to 10% by weight relative to the total weight of the second composition and a gelling polymer.
