When the OzFest 2 group took a tarmac tour of SYD last May, one of the stops was the airplane washing station. A 747 was getting the full treatment. Our guide/driver explained that drag caused by dirt makes a noticeable difference in fuel consumption, so they wash the planes every few weeks. Managing all the water it uses is a big issue, especially in Australia's relatively dry climate; they pay a lot of attention to reclaiming/recycling it.

Air France (or any other airline) may not care much about its fleet's beauty, but I suspect they care a lot about its fuel consumption. Nice, smooth paint (or clean, polished aluminum) slides through the air better.