Abstract: A profile bar to be locked to a panel. A frame has a shape that is a continuous profile. The frame includes a slot in which the panel can be installed. A first side and a second side of the slot delimit the slot and support the panel. A protrusion is provided on the first side of the slot and fitted to be placed in a groove in the panel. A locking piece includes a locking part which can be inserted between the panel in the slot. The locking part makes the slot narrower, to push the panel against the protrusion and to support the panel such that the protrusion remains in the groove of the panel. The detachment of the panel from the frame is prevented. A panel system includes a planar panel equipped with at least one locking groove and profile bar to be locked to the panel.