The present invention relates to a process for treating human keratin fibres such as the hair, which comprises: i) a step of applying to the human keratin fibres a composition comprising: —at least one plant wax: —at least 60% by weight of water relative to the total weight of the composition; ii) followed by a step of heating the keratin fibres by means of a heating appliance at a temperature ranging from 80° C. to 160° C., preferably from 110° C. to 50° C., more preferably from 120° C. to 150° C., which is moved along the fibres, iii) optionally followed by a step of rinsing the keratin fibres.