An assembly consists of a gas bag module (16; 16null; 116; 216; 316; 416; 516; 616) and a vehicle body part (10; 510) including a ventilation channel (34; 134; 234; 334; 434; 534; 634) for ventilating a front windscreen. The ventilation channel is arranged between the front windscreen (12; 112; 212; 312; 412; 512; 612) and the gas bag module. The gas bag module (16; 16null; 116; 216; 316; 416; 516; 616) has a gas bag (52; 52null; 52null; 152; 252; 352; 452; 552; 652) folded to form a gas bag package and a gas lance (54; 54null; 54null; 154; 254; 354; 454; 554; 454null; 654) through which gas can be directed into the gas bag. The gas bag module has an ejection opening (50; 50null; 50null; 150; 250; 350; 450) through which the gas bag can be ejected on inflation. The gas bag package comprises first and second partial packages, of which the first partial package (52a; 152a; 252a; 352a; 452a; 552a; 652a) is arranged closer to the ejection opening, whereas the second partial package (52b; 152b; 252b; 352b; 452b; 552b; 652b) is arranged further away with respect to the ejection opening. The gas lance (54; 54null; 54null; 154; 154null; 254; 354; 454; 554; 454null; 654) is arranged in the gas bag module such that only the first partial package (52a; 152a; 252a; 352a; 452a; 552a; 652a) is situated between the ejection opening (50; 50null; 50null; 150; 250; 350; 450) and the gas lance.