Germany's Tony Martin retained the lead in the Paris-Nice after Saturday's stormy seventh stage was won by French rider Remy Di Gregorio.

This first major-stage race of the season is known as the Race to the 'Sun' but there was little of that in evidence as strong winds and rain made life difficult for the peloton during the 215.5km ride.

One man singing in the rain was Marseille-born Di Gregorio, who made his winning move 13km from the finish to edge home a chasing group headed by Spain's Olympic champion Samuel Sanchez.

The longest stage of the race was marked by a clutch of falls as the slippery surface took its toll and there were a number of key retirements, including Frank Schleck, suffering from a stomach problem, Ireland's Nicolas Roche and Slovak rider Peter Sagan, who was regarded as a potential winner of the race.

For Di Grigorio, the 25-year-old Astana team member, this was his second career stage win after picking up a stage on the 2006 Tour de l'Avenir.

HTC-Highroad rider Martin moved to the top of the overall standings after winning Friday's sixth stage time trial.