Assembly comprising a vehicle body part and an airbag module

The unit has a ventilation channel (34) between a front screen (12) and the airbag module (16) for ventilating the front screen. The airbag module has an airbag pack with two sub-packs, of which the first is closer to an ejection opening, and a gas lance arranged in the airbag module so that only part of the first sub-pack is between the ejection opening and lance.