Current leader Thor Hushovd of Norway, third and second in the two previous stages, will hope to win at last, with Australian Robbie McEwen his most serious rival in a bunch sprint.
Armstrong, bidding for an unprecedented sixth tour victory, will have other concerns.
A 64.5-km team time trial from Cambrai to Arras on Wednesday is expected to establish the first meaningful hierarchy on this Tour, with the Texan back in his usual place.
In the meantime the U.S. Postal team leader and his team mates will try to avoid crashes and incidents, hoping the start in Waterloo will not incite the sprinters into launching too fierce a battle.
