The invention relates to a glass panel element (1) with a fastening element (2) for using in a container (6), in particular for using in a showcase. The fastening element (2) has a profiled edge strip (3) for fixing to the container (6) in a form-fitting manner. Said fastening element (2) is adhesively connected with a lateral surface (4) of the glass panel element (1). A thickness (D1) of the fastening element (2) corresponds to a thickness (D2) of the glass panel element (1). A fastening element (2) is arranged on each facing side of the glass panel element (1) and adhesively connected with said glass panel element (1). The profiled edge strip (3) and the glass panel element (1) close in a flush manner. The fastening element (2) is made of aluminium. The invention also relates to a glass showcase comprising at least one glass panel element (1) according to the invention.