The city of lights has a dark side, the catacombs of course. Not only are crews of taggers and graffiti artists painting walls up high above the roof tops like this round lettered throw up in Place Italie
|look at that white sky, shall I say achromic?|
and trucks you can see almost anywhere
but they go underground hauling their materials down man holes and through metro tunnels to paint images like the Hokusai wave in a room called the Beach.
Here is a blogpost by GAKURANMAN whose photo I borrowed.
National Graphic printed a special issue in Febrary 2011 about the underground art scene in Paris. Here is a video on vimeo about sous-street art in Paris. Don Duncan did a story in 2010 for The Wall Street Journal.
I think I'll take their word for granted and just stay above the tarmac.