The present invention provides for a mounting envelope (1) for receiving a curtain-airbag and for attaching the curtain-airbag to the interior of a vehicle, in particular to the roof frame of a vehicle. The mounting envelope (1) comprises a longitudinal tear-line (3) which is configured to break in the event of a curtain air-bag deployment and extends in a longitudinal direction (L) of the mounting envelope. The mounting envelope is characterized in that it covers at least a major part of a curtain-airbag and in that it comprises at least additional vertical tear-line (7), preferably extending in a direction (V) substantially perpendicular to the longitudinal direction (L).