Assembly including a body-in-white and tailgate for automobile

An assembly including a body of an automobile and a tailgate mounted on the body so as to be movable between an open position and a closed position, comprising:

• an opening assistance device mounted between the body and the tailgate in order to apply a pushing force on the tailgate that tends to move the tailgate into the open position, the opening assistance device comprising a cylinder applying a pushing force along a first when the tailgate is placed in the closed position;
• at least one abutment provided on the body, for applying on the opening assistance device, when the tailgate is in the closed position, a force opposite to the pushing force thereof so that the tailgate is not more than barely subjected to the pushing force of the opening assistance means,
• a connecting part connecting the cylinder to the tailgate and means for centering the connecting part with respect to the body, when the tailgate is placed in the closed position on the body,
• the at least one abutments being designed so that the connecting part rests against the at least one abutment when the tailgate is placed in closed position on the body and at least one of the at least one abutments comprising a groove in which a projection of shape substantially complementary to that of the groove, fastened to the connecting part, can engage when the tailgate is placed in the closed position on the body.