An acoustic treatment structure related to a leading edge onto which an aerodynamic stream flows, in particular at an air intake of an aircraft nacelle, includes—from the outside to the inside—at least one acoustically resistive substructure (30), at least one alveolar substructure including strips (32) of cells, arranged in a direction that is essentially perpendicular to the direction of flow of the aerodynamic stream, and at least one reflective layer (34). Each strip (32) includes a first part that insulates the strips from one another, called a support, with a U-shaped cross-section in the longitudinal direction, whose open surface that is opposite to the bottom of the U shape is flattened against the acoustically resistive substructure (30), and at least a second part, called partitioning, making it possible to partition the space that is delimited by the support and the acoustically resistive substructure (30) into cells.