The invention relates to an arrangement for securing a vertical panel (14) in a longitudinal groove (28), the panel (14) comprising an inner face (20) and an outer face (22), the securing being carried out by transverse clamping between transversely opposed wedges (36A, 36B; 38A, 38B), the arrangement comprising: an upper outer wedge (38A) and a lower outer wedge (38B) which are each positioned between an outer face (34) of the groove (28) and the outer vertical face (22) of the panel (14); at least two movable transmission members (62A, 62B) which are each capable of transmitting a sliding force to an associated outer wedge (38A, 38B), the force being applied from an inner side (24) of the panel (14); the arrangement is characterized in that the upper and lower outer wedges (38A, 38B) slide vertically upwards from the released position thereof to the clamped position thereof above the released position.