The invention relates to a front portion (1) of the structure of a motor vehicle including a structural unit (2) inserted in the longitudinal direction of the vehicle between at least one front crossmember (3, 4) and a firewall (19) for closing the cabin of the vehicle, characterized in that the structural unit (2) includes at least one outer shell (5, 6) and at least one inner shell (7, 8) which are contiguous with one another, the shells being configured so as to define, on each side of the vehicle, at least one generally sleeve-shaped stiffener (9-12) extending substantially in the longitudinal direction (X) of the vehicle, the stiffener (9-12) forming a pathway for transmitting and absorbing a force between a corresponding end of the front crossmember (3, 4) and the firewall (19).