The present invention relates to a method for semipermanent straightening and dyeing of the hair in two steps. The method uses a first composition (straightening composition) comprising at least one carboxylic acid of the Formula (I), and a second composition (dye composition) comprising at least one hair dye, optionally at least one alkalizing agent and optionally at least one oxidizing agent. The hair is treated with the said compositions successively, so that the dyeing treatment is performed directly after the straightening treatment.
