Germany's sprinter Marcel Kittel, second left, crosses the finish line with a fraction of a second difference ahead of Norway's Edvald Boasson Hagen, right, to win the seventh stage of the Tour de France. Photo: Christophe Ena/AP

Marcel Kittel pipped Edvald Boasson Hagen by the tiniest of margins in a photo finish to the Tour de France seventh stage on Friday.

To the naked eye, and even television pictures, it seemed impossible to separate the pair as they crossed the line in Nuits Saint-Georges.

But after a nervous wait and several inclusive views of the finish line battle, Quick-Step's Kittel was awarded his third stage win of the year and 12th in total, matching the record for a German held by Erik Zabel.

It was a bitter pill to swallow for Norwegian Boasson Hagen who looked all set for victory until a late charge by the irrepressible Kittel, already winner of the second and sixth stages, although far more convincingly.

Australian Michael Matthews finished third as reigning champion Chris Froome maintained his overall lead at the end of the 213.5km stage from Troyes on another day of minimal drama, until the controversial finish.

For the overall contenders it was another day to simply stay out of trouble before the weekend's back-to-back mountain stages when the yellow jersey battle will return to centre stage.

In the meantime, the top sprinters will have two days to lick their wounds and try to conjure up a way to stop Kittel.