Permanent restructuring process of keratinous fibers, preferably human keratinous fibers e.g. hair, comprises: applying a reducing composition (I) (containing a reducing agent and an organic/mineral salt) on the fibers, hair-styling and applying a composition (containing polymer fixers e.g. anionic or amphoteric polymer fixer in an aqueous or (hydro)alcoholic medium); and applying a fixing composition (II) containing a fixing agent.