Madeline Buthane is a tour-group leader in Rennes-le-Château. She has extensive knowledge of the region and of the various theories regarding the treasure in the region. She is voiced by Jennifer Hale.
The following has spoilers for Gabriel Knight 3: Blood of the Sacred, Blood of the Damned
Buthane is later revealed to be an agent for French intelligence. She is seen using sex to get information from Abbe Arnaud, and attempts the same with both Gabriel and Mosely, though both reject her. Part of her job is to test some of the latest theories France's intelligence agencies have about where the Rennes treasure is. When one of these theories is preempted by Mosely, she becomes suspicious of him, but claims not to know the CIA was behind the hack into her system until Mosely admits to being a part of the agency.
In the French version of the game, she is renamed Madeline Muselier.