The present invention relates to a cosmetic process for treating keratin materials, which can give them, especially in a long-lasting and reversible manner, interesting cosmetic properties this process comprising the application to said materials:in a first stage, of a cosmetic composition comprising at least one graftable species, comprising at least one unit of formula (Ia):and in a second stage, of a cosmetic composition comprising at least one cosmetic active agent bearing at least one unit of formula (Ia):The invention also relates to a kit comprising said compositions.
