A panel for acoustic treatment connected to a surface of an aircraft, includes—from the outside to the inside—an acoustically resistive porous layer, at least one alveolar structure, and a reflective or impermeable layer, whereby the acoustically resistive porous layer includes—at the outside surface that can be in contact with the aerodynamic flows—one sheet or piece of sheet metal including open zones (14) that allow sound waves to pass and filled zones (16) that do not allow sound waves to pass, characterized in that the sheet or piece of sheet metal of the acoustically resistive layer includes sets of microperforations (18), whereby each set of microperforations forms an open zone (14), the sets of microperforations being separated from one another by at least one series of bands separated by filled zones (16).