The Paris Underground story comes out in February. See the pictures at NGM.com here.
As part of that assignment I spent a long time in front of the Opera Garnier metro station. I wasn't trying to shoot a time lapse. I was trying to get the right people at the right time in the right place. Sometimes putting a camera on a tripod is the best way to do this so I set up my tripod and shot pictures for a couple of hours. Somehow having a camera on a 7 foot tripod (CT-313) is less intimidating to people that holding the camera in your hand. I held a remote control and fired pictures whenever I thought interesting people were walking through the frame. Subway sounds were recorded by Daniel Voirin on a Zoom H4n and Carmen is from old wax recordings.