The present invention relates to a prosthesis (200) comprising:—at least one layer of a flexible mesh (1) delimited by a peripheral outer edge (1a), said mesh having a first color, and—at least one layer (2) of porous material fixed to said mesh substantially along the perimeter of said peripheral outer edge, said layer of porous material being recessed at its central part (4), said layer of porous material having a second color, different from said first color.