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.