Rlvlk

Corrected entry: If it is indeed a GPS receiver used by the police to track the couple's location and movement in the interior of The Louvre, the device would not have functioned indoors as GPS needs a line of sight to the sky. The more plausible part is when Sophie later puts the device in a bar of soap and tossed it out the window onto a passing truck, then it would receive satellite signals that the police would track it moving away. I would have agreed with the indoor scene if the device was a radio beacon, but if I remember right, even the book said it was a GPS.