Capsule (1) for the preparation of a beverage in a beverage preparation device comprising a cup-like body (2), a sealing cover (3) for closing the cup-like body； a flange (4) for the cover to seal thereon； the cup-like body being formed of paper-based material comprising at least one gas barrier layer with a cavity wall (5) containing beverage ingredients； wherein the flange (4) is sealingly attached to body and the flange is formed of a first polymer and a second gas barrier polymer； the second polymer being a gas barrier layer overlapping with the cup-like body.
