The invention relates to a metal element (12) for anchoring an anti-erosion coating that is intended to be fastened alone in an isolated manner to a metal wall or assembled with other identical anchoring elements. The anchoring element (12) has an edge (12a) for fastening to said metal wall and an anchoring body firmly attached to the fastening edge (12a) and having an upper edge (12b) that is away from the fastening edge and intended to be covered by a composite material of concrete type. A section of this upper edge (12b), which is not intended to be juxtaposed and assembled with an upper edge of an identical anchoring element, is provided with a delimiting tab (16) in order to delimit a height of composite material that must cover the upper edge (12b) of said anchoring element, said delimiting tab (16) having a delimiting edge (18) that is a predetermined distance away from a plane defined by the upper edge (12b) of the anchoring element.