A trim element that includes a supporting element having a main surface extending between two opposite edges, a lining layer covering the main surface and the edges of the supporting layer, and a skin surrounding the lining layer. At least one of the edges includes a reinforcing element movably mounted relative to the supporting element between a retracted position and a deployed position wherein at least one portion of the reinforcing element protects from the main surface in such a way as to reduce the length of the portion of the reinforcing element extending in relation to the main surface, the projecting portion being surrounded by the lining layer.