French police say she was struck Saturday while trying to cross the road in Alsace in eastern France during the 14th stage.
Commander Christophe Blanc told France Info radio that the motorcycle driver was from a unit of the Republican Guard and could not avoid hitting the woman. The driver was helping supervise the race.
The driver fell off his bike, which then hit and injured two other people. Their lives are not in danger. One of the injured was a mother with a child in her arms, but the youngster was not hurt.