I noticed one characteristic at the rear of the Merc that's shared by the Honda Insight (gen 1) and even the latest gen Metros.
In each of those cars, the "haunch" over the rear wheel isn't only a styling feature.
It lets them place the wheel at the "outside" of the lower bodywork, while tapering the greenhouse above it significantly more. That line serves as the transition from the plane of the outside of the wheel to the greenhouse boat-tailing.
Insight gen 1's is most pronounced:
Of course they could all have done a smoth transition as well and eliminated the "line".