Use of cosmetic composition comprising at least one organic silicon compound comprising silanes containing a silicon atom and siloxanes comprising two or three silicon atoms, where the organic silicon compounds further comprises at least one basic chemical functions and one or more hydroxyl groups or hydrolysable groups per molecule, and the silanes are organosilane compound (I), in combination with a care composition and/or washing composition for keratin fibers, preferably human keratin fiber as hair, is claimed. Use of cosmetic composition comprising at least one organic silicon compound comprising silanes containing a silicon atom and siloxanes comprising two or three silicon atoms, where the organic silicon compounds further comprises at least one basic chemical functions and one or more hydroxyl groups or hydrolysable groups per molecule, and the silanes are organosilane compound of formula (R 1)(R 2)N-R 3-Si(R 4)(R 5)(R 6)) (I), in combination with a care composition and/or washing composition for keratin fibers, preferably human keratin fiber as hair, where the cosmetic composition and the care composition and/or washing composition are applied sequentially to the keratin fibers, is claimed. R 4halo, OR 1aor R 11agroup； R 5halo, OR 2aor R 22agroup； R 6halo, OR 3aor R 33agroup； and R 1, R 2, R 3, R 1a, R 2a, R 3a, R 11a, R 22a, R 33aoptionally saturated, optionally linear hydrocarbon group, optionally bearing additional chemical groups. Provided that: R 1, R 2, R 1a, R 2a and R 3agroups are H； at least two of R 4, R 5and R 6groups are OR 1a, OR 2aand OR 3a； and at least two of R 1a, R 2aand R 3a groups are different from hydrogen. An independent claim is included for a process for cosmetic treatment of keratin fibers, preferably human keratin fibers including hair, comprising applying sequentially the cosmetic composition at least one silicon organic compounds in the medium and a care and/or washing composition, to the keratin fiber, and optionally rinsing af
