An electronic shelf label for displaying information. The electronic shelf label includes: a casing including at least one side surface, a front side and a back side; an information display area arranged in the front side; and at least two curved recesses arranged at a distance from each other in the at least one side surface, the at least two recesses are intended for attachment of an external information display sign to the electronic shelf label. Also, an information display sign for use in combination with the electronic shelf label.