A leading edge slat of a wing element of an aircraft. The aircraft defining a mark including a main fuselage axis x and a spanwise axis y. The wing procuring a lift along an axis z. The wing element having a skin forming the leading edge slat, a spar linked to the skin and a stiffening structure linked on the leading edge side to the spar and to the skin. The stiffening structure being formed from a formed sheet metal having a plurality of bosses distributed according to the length of the leading edge. The bosses extending between the spar and the inner face of the skin.