The invention relates to a process for treating keratin fibres that are not artificially dyed, in particular human keratin fibres such as the hair, comprising: (i) a step of applying an oxidized polysaccharide, (ii) a step of heating to a temperature of at least 100° C., (iii) a step of applying an amino silicone. The process makes it possible to obtain good hair-conditioning cosmetic properties, with a long-lasting effect.
