A method for producing a metal insert for protecting a leading or trailing edge of a compressor vane of an aeronautical machine made of a composite material, by stamping sheets and diffusion bonding between the sheets. The method includes: initially shaping the sheets by stamping to approximate the sheets to a shape of a suction side and pressure side of the insert; producing a core shaped inner cavity of the metal insert to be manufactured, one of the surfaces thereof reproducing an inner shape of the suction side of the insert and the other surface reproducing an inner shape of the pressure side of the insert; positioning the sheets around the core and securing the assembly; applying a vacuum and sealing the assembly by bonding; assembling the assembly by hot isostatic compression; cutting the assembly to extract the core and separate the insert; producing an outer profile of the insert by a final machining.