Flat-shaped composite material for manufacturing a package , comprising: - a polymer outer layer, - a polymer inner layer, - a fibrous support layer, which is arranged between the polymer outer layer and the polymer inner layer, - wherein the flat-shaped composite material has a plurality of fold lines, which are arranged and designed such that a closed package can be manufactured by folding the flat-shaped composite material along the fold lines and by connecting seam surfaces of the flat-shaped composite material , - a sleeve surface , wherein the sleeve surface comprises a front surface , a first side surface , a second side surface , a first rear surface and a second rear surface , - base surfaces , wherein the base surfaces comprise triangular base surfaces and quadrangular base surfaces (5"), and - gable surfaces , wherein the gable surfaces comprise triangular gable surfaces and quadrangular gable surfaces (6"), - wherein the base surfaces and the gable surfaces are arranged on opposite sides of the sleeve surface , - wherein the sleeve surface has at least one stress-relief surface , which is arranged between the front surface and one of the two side surfaces , - wherein a first sleeve fold line is provided between the stress-relief surface and the adjoining front surface , and - wherein a second sleeve fold line (18") is provided between the stress-relief surface and the adjoining side surface , characterised in that the at least one stress-relief surface adjoins a quadrangular base surface (5") in the region of the base surfaces and adjoins a triangular gable surface in the region of the gable surfaces . - a polymer outer layer, - a polymer inner layer, - a fibrous support layer, which is arranged between the polymer outer layer and the polymer inner layer, - wherein the flat-shaped composite material has a plurality of fold lines, which are arranged and designed such that a closed package can be manufactured by folding the flat-shaped composite material along the fold lines and by connecting seam surfaces of the flat-shaped composite material , - a sleeve surface , wherein the sleeve surface comprises a front surface , a first side surface , a second side surface , a first rear surface and a second rear surface , - base surfaces , wherein the base surfaces comprise triangular base surfaces and quadrangular base surfaces (5"), and - gable surfaces , wherein the gable surfaces comprise triangular gable surfaces and quadrangular gable surfaces (6"), - wherein the base surfaces and the gable surfaces are arranged on opposite sides of the sleeve surface , - wherein the sleeve surface has at least one stress-relief surface , which is arranged between the front surface and one of the two side surfaces , - wherein a first sleeve fold line is provided between the stress-relief surface and the adjoining front surface , and - wherein a second sleeve fold line (18") is provided between the stress-relief surface and the adjoining side surface , characterised in that the at least one stress-relief surface adjoins a quadrangular base surface (5") in the region of the base surfaces and adjoins a triangular gable surface in the region of the gable surfaces . <EOS>