Margaretha Geertruida "Grietje" Zelle, stage name Mata Hari, was not a spy.
"After the war, the French admitted that they had no real evidence against her. The conclusion by most modern historians has been that she was shot not because she was running a honey trap operation, but to send a powerful message to any women who might be tempted to follow her example. The lesson here, perhaps, is that resembling a honey trap can be as dangerous as actually being one."
The History of the Honey Trap, from Foreign Policy Magazine>>