Disclosed herein is a semipermanent hair shaping method comprising: (a) applying onto the hair a first composition comprising, in a cosmetically acceptable medium, at least one solubilized fixing polymer chosen from anionic and amphoteric polymers, this application being optionally followed by a resting time for said first composition, (b) applying onto the hair a second composition comprising in a cosmetically acceptable medium at least one acid chosen from mineral and organic acids, such application being optionally followed by a resting time for said second composition, where step b) is conducted prior to or after step a), (c) rinsing the hair, and (d) shaping the hair either after applying the first composition of step a), or after applying the second composition of step b) and prior to the rinsing step c).