At first glance there would seem to be little reason to even notice number 1 Bis Rue Chapon in the 3rd arrondissement of Paris. The graffiti-covered, ordinary green door near the end of the street offers no reason to linger. But all is not as it seems.

A small sign next to the nondescript door reads “J.B. & S.B. Specialists,” which offers little clue as to what the occupants of the building do. Knock at the door for an answer and you’ll be waiting a very long time. Because 1 Bis Rue Chapon is not a real door, or at least, not a door that leads to anywhere. The address, the door, and the sign are all just a façade, mounted on a blank wall.

“J.B. & S.B. Specialists” are in fact artists Julien Berthier and Simon Boudvin. The duo created the façade as a piece of trompe l’oeil street art. Early one morning in 2006 the pair installed the façade, specially designed to fill the blank wall and following all the local architectural codes, in less than 30 minutes.

They gave the empty wall a fake address too: “1 Bis.” (“Bis,” meaning repeat or twice, designates addresses for divided lots, like 1B or 1 1/2.)

The façade is an installation created to represent all the common but potentially mysterious doors and gateways that exist in cities everywhere. It was initially imagined to be temporary, yet over a decade later—to the artists’ surprise—it’s still there.

The fake Parisian door and wall have been tagged and sprayed many times over the years, and at least once the city’s municipal cleanup team actually cleaned up the graffitied façade. Though if the city authorities sent an invoice for that work to 1 Bis Rue Chapon, they’ll be waiting a very long time to be paid.