An improvement of a process for permanently reshaping keratin fibres, comprising the application to the keratin fibres, before the reducing operation and/or after the fixing operation, of a pre-treatment and/or post-treatment cosmetic composition comprising, in a cosmetically acceptable vehicle, at least one aminosilicone microemulsion, the number-average primary size of the particles in the at least one microemulsion ranging from 3 to 70 nm.
