The invention relates to a ramp assembly that is integrated into and flush with an area of the floor of a vehicle, which area is contiguous to a door, the ramp being able to adopt two end positions, a rest position in which a platform is concealed inside the vehicle, and an operative ramp position in which the platform is disposed in a plane sloping from the floor of the vehicle to a surface located at a lower height, from which people enter. The ramp assembly is provided with a lifting mechanism for minimising the height difference between the floor and the rear side of the platform in the operative ramp position, and comprises at least one rocking piece hingedly disposed between movement transmission means and the platform, and at least one wedge that makes contact with a lower rolling bearing.
