Method for producing a trim element having a three-dimensional shape and comprising at least a layer of ligneous material, the method comprising the following steps: - providing a substantially planar layer of ligneous material, - shaping the layer of ligneous material in order to obtain the three-dimensional shape of the trim element to be produced, wherein the shaping step comprises at least the following successive steps: - deforming the layer of ligneous material to an intermediate shape between the initial planar shape and the final three-dimensional shape of the layer of ligneous material, - stabilizing the layer of ligneous material having the intermediate shape in order to reach the moisture equilibrium of the ligneous material, - deforming the layer of ligneous material to the final three-dimensional shape, wherein the step of deforming the layer of ligneous material from the initial planar shape to the intermediate shape comprises the step of placing the layer of ligneous material having the initial shape in a first forming tool comprising a first part and a second part, said parts defining together a space having the intermediate shape of the layer of ligneous material and applying a pressure on the layer of ligneous material between the first and second parts (14, 16) of the first forming tool such that said layer acquires the intermediate shape, wherein the step of deforming the layer of ligneous material from the intermediate shape to the final shape comprises the step of placing the layer of ligneous material having the intermediate shape in a second forming tool comprising a first part and a second part, said parts defining together a space having the final shape of the layer of ligneous material and applying a pressure on the layer of ligneous material between the first and second parts (14, 24) of the second forming tool such that said layer acquires the final shape, characterized in that the stabilizing step is a humidifying step, wherein the layer of ligneous material is humidified to reach the moisture equilibrium of the ligneous material and wherein the layer of ligneous material is humidified to reach a moisture of the layer of ligneous material substantially comprised between 7% and 9%, and in that the second part of the second forming tool comprises at least one drawer movable between a retracted position, wherein the second part can be moved relative to the first part of the second forming tool, and an active position without interfering with said first part, wherein the second part defines with the first part a final three-dimensional shape comprising at least one undercut. - providing a substantially planar layer of ligneous material, - shaping the layer of ligneous material in order to obtain the three-dimensional shape of the trim element to be produced, - deforming the layer of ligneous material to an intermediate shape between the initial planar shape and the final three-dimensional shape of the layer of ligneous material, - stabilizing the layer of ligneous material having the intermediate shape in order to reach the moisture equilibrium of the ligneous material, - deforming the layer of ligneous material to the final three-dimensional shape, - deforming the layer of ligneous material to the final three-dimensional shape,