Structure (1) for mounting, on a building wall, at least one frame (50) consisting of a rectangular framework (51), comprising a carcass (2) made of at least two uprights (3) and at least two crossbars (4) assembled so as to form at least one rectangular underframe (15) adapted for receiving a frame (50), and means for fixing at least one frame on the carcass, each upright (3) having a central core (31) bordered by two side wings (32, 33) comprising recesses (38, 39) for receiving the crossbars (4). Each crossbar (4) has a central core (40) and side wings (41, 42) comprising recesses in line with the uprights (3) at the intersections between the crossbars (4) and the uprights (3) in such a way that the wings of the uprights (3) and the crossbars (4), extending on the inner periphery of the rectangular underframe (15), form a projecting border on which a frame (5) may be fitted. Wall provided with a structure of this type on which panel-holding frames are mounted.