Arrangement for securing a vertical panel in a longitudinal groove open vertically upwards for receiving a lower edge of the panel, the panel including an inner face and an outer face, securing being carried out by transverse tightening between transversely opposed wedges (36A, 36B; 38A, 38B), the arrangement including: - at least a first upper outer wedge and at least a second lower outer wedge which are each interposed between a vertical outer face of the groove and the vertical outer face of the panel, each of the outer wedges (38A, 38B) being slidably mounted vertically in the groove between an untightened position and a tightened position between the outer face of the groove and the outer face of the panel; - at least two mobile transmission members (62A, 62B) which are interposed between the edge of the panel and a bottom of the groove and which are each capable of transmitting a sliding force to an associated outer wedge (38A, 38B) applied from an inner side of the panel; the upper and lower outer wedges (38A, 38B) sliding vertically, the second lower outer wedge sliding vertically upwards from its untightened position towards its tightened position located above the untightened position; characterised in that the first upper outer wedge slides vertically upwards from its untightened position towards its tightened position located above the untightened position. the panel including an inner face and an outer face, securing being carried out by transverse tightening between transversely opposed wedges (36A, 36B; 38A, 38B), the arrangement including: - at least a first upper outer wedge and at least a second lower outer wedge which are each interposed between a vertical outer face of the groove and the vertical outer face of the panel, each of the outer wedges (38A, 38B) being slidably mounted vertically in the groove between an untightened position and a tightened position between the outer face of the groove and the outer face of the panel; - at least two mobile transmission members (62A, 62B) which are interposed between the edge of the panel and a bottom of the groove and which are each capable of transmitting a sliding force to an associated outer wedge (38A, 38B) applied from an inner side of the panel; - at least a first upper outer wedge and at least a second lower outer wedge which are each interposed between a vertical outer face of the groove and the vertical outer face of the panel, each of the outer wedges (38A, 38B) being slidably mounted vertically in the groove between an untightened position and a tightened position between the outer face of the groove and the outer face of the panel; - at least two mobile transmission members (62A, 62B) which are interposed between the edge of the panel and a bottom of the groove and which are each capable of transmitting a sliding force to an associated outer wedge (38A, 38B) applied from an inner side of the panel; the upper and lower outer wedges (38A, 38B) sliding vertically, the second lower outer wedge sliding vertically upwards from its untightened position towards its tightened position located above the untightened position; characterised in that the first upper outer wedge slides vertically upwards from its untightened position towards its tightened position located above the untightened position.