COMPIEGNE, France - There will be much to lose and little to gain in Wednesday's fourth stage of the Tour de France.

With four fourth-category climbs along the 193-km stage from Villers-Cotteret to Joigny, a single mistake could end up in a rider losing a lot of time.

"This stage is the first really lumpy one of the race," said Tour competition director Jean-Francois Pescheux.

"It could leave some of the small fry struggling to keep pace. If the field gets lined out, just one lapse in concentration can lead to a rider losing contact with the main field.

"This should be an interesting stage, with a lot of action."

However, the stage should end in a bunch sprint and former world champion Tom Boonen, fourth in Tuesday's third stage, will try to snatch his first Tour stage victory in two years.

Swiss Fabian Cancellara, who retained the overall lead when he won the stage on Tuesday, has made it clear he will defend his yellow jersey.

"If the other teams want a piece of the cake, they will have to come and get it," the Team CSC rider said.

German Andreas Kloeden of Astana is second 33 seconds behind Cancellara with Saunier Duval's David Millar of Britain third a further 11 seconds back.