I achieved 5,9 l/100km per the board computer on the mostly-autoroute drive between Luxembourg, Arlon, and Metz. Some country roads, a bit of urban driving, and mostly 130 on the freeways except in France where the grindingly slow 90 limit was painful. Not too bad for a boosted 4-cyl petrol though.
Then the long-haul drive, 324km from Thionville back to home in Germany netted 6,5 l/100km with the climatisation on most of the time. Drove mostly 130-140, with a couple extended sprints up to 170 on the "when will this boredom end" A6.