Sagan claims his second Tour stage victory

It was the Liquigas-Cannondale rider's second stage win having triumphed in Sunday's first full stage.

Fabian Cancellara (RadioShack-Nissan) retained his yellow jersey lead on a general classification that remained largely unchanged at the top.

It was the tour's first appearance in France this year following the prologue and two stages across the border in southern Belgium, and the tough final 50km saw a number of crashes and incidents.

Yellow jersey contenders Team Sky were the first to suffer a setback when Kanstantsin Sivtsov was forced to retire.

Sivtsov, one of Sky's support riders for race favourite Bradley Wiggins, was one of several riders caught up in a crash just after the Cote de l'Eperche around 140km into the race.

He sat on the ground and waited for medical advice, apparently complaining of a sore knee, before his retirement was announced minutes later.

Sivtsov became the first of the 198-strong peloton to withdraw from this year's race, which ends in Paris on July 22, but he was not alone with more coming shortly after.

Other riders to be caught up in the spill were Tyler Farrar (Garmin-Sharp) and Pablo Urtasun (Euskaltel-Euskadi).

The crash, which happened on a tight road, left many riders scrambling over the grass verges with their bike in a bid to get moving.

Giampaolo Caruso of Katusha also suffered injuries when he fell while Australian champion Simon Gerrans (Orica-GreenEDGE) went over the handlebars and into a fence after he collided with a bike lying on the ground.

Farrar and Gerrans were eventually paced back to the peloton, which at that point had a 3min 55sec deficit on a reduced breakaway group.

The third stage had been feared by a number of different teams and riders due to a succession of six small climbs, five of which came in the last 35km, on tight roads leading to the finish line.

And those fears were confirmed when another crash on the next climb, the Mont Violette, prompted the withdrawal of sprinter Jose Joaquin Rojas (Movistar), who finished second in the green jersey points competition in 2011.

The 22-year-old Sagan eventually won a tight finish up the final rise, edging ahead of Edvald Boasson Hagen (Sky) and Peter Velits (Omega Pharma-QuickStep).

Cancellera was fourth with last year's tour winner Cadel Evans (BMC) in sixth place.

Earlier a five man break involving Andriy Grivko (Astana), Giovanni Bernaudeau (Europcar)), Ruben Perez (EUskaltel-Euskadi), Sebastien Minard (AG2R) and Michael Morkov (Saxo Bank-Tinkoff Bank) rode out to a lead of over 5min before the fight back came from the peloton.

The intermediate sprint saw Minard took first place and maximum points while Mark Cavendish won the bunch gallop for sixth, hoping to build on his green jersey total.

Meanwhile Morkov, who has been in every break, went unchallenged on the first climb, adding to his tally of points in the race for the polka-dot jersey.

However the breaks survival was always in doubt and Bernaudeau was the first to drop off the back and the rest fell one by one as as the closing climbs took their toll.

Grivko was the last of the five riders to crack, back in the peloton with less than 10km left to run.

Ivan Basso (Liquigas-Cannondale) led over the penultimate climb and shortly afterward Sylvain Chavanel (Omega Pharma-QuickStep) went on the attack, but was caught with only 500m to go.

On the final climb Wout Poels (Vacansoleil-DCM) rode to the front followed by Orica-GreenEDGE's Michael Albasini, who led around the second last turn.

Lieuwe Westra (Vacansoleil-DCM) then crashed, splitting the remnants of the peloton, and Albasini's bid for the stage win ended when Sagan started his sprint, leaving the peloton behind.

Stage 3: 197km, Orchies to Boulogne-sur-Mer

1 Peter Sagan (SVK) Liquigas-Cannondale 4hr 42min 58sec          
2 Edvald Boasson Hagen (NOR) Sky           
3 Peter Velits (SVK) Omega Pharma-QuickStep           
4 Fabian Cancellara (SWI) RadioShack-Nissan           
5 Michael Albasini (SWI) Orica GreenEDGE          
6 Cadel Evans (AUS) BMC            
7 Nicolas Roche (IRL) AG2R            
8 Samuel Sanchez (ESP) Euskaltel-Euskadi           
9 Bauke Mollema (NED) Rabobank           
10 Vincenzo Nibali (ITA) Liquigas-Cannondale           

General classification

1 Fabian Cancellara (SWI) RadioShack-Nissan 14hr 45min 30sec      
2 Bradley Wiggins (GBR) Sky 0:00:07      
3 Sylvain Chavanel (FRA) Omega Pharma-Quickstep            
4 Tejay Van Garderen (USA) BMC 0:00:10      
5 Edvald Boasson Hagen (NOR) Sky 0:00:11      
6 Cadel Evans (AUS) BMC 0:00:17      
7 Vincenzo Nibali (ITA) Liquigas-Cannondale 0:00:18      
8 Ryder Hesjedal (CAN) Garmin-Sharp            
9 Andreas Kloden (GER) RadioShack-Nissan 0:00:19      
10 Bauke Mollema (NED) Rabobank 0:00:21