Tour de France debutant Fernando Gaviria has proved he is the No.1 sprinter in this year's race, claiming his second stage.
Australian favourite Richie Porte stayed out of trouble ahead of his next big test in two days, but there was more crash carnage on stage four.
French hope Romain Bardet lost a key lieutenant when Ag2r teammate Axel Domont fractured his collarbone in a crash inside the last 5km.
Last year's runner-up Rigoberto Uran was caught in the same pile-up, but the Education First-Drapac team made sure their Colombian star did not lose any time.
Belgian Tiesj Benoot (Lotto Soudal) finished the stage with a bloodied face and a dislocated shoulder.
The overall hopes of Russian Ilnur Zakarin (Katusha-Alpecin) took a major hit when he lost 59 seconds.
But Porte's BMC team avoided the crash and their Belgian ace Greg Van Avermaet retained the yellow jersey.
Porte and the other overall hopes will try to gain time on stage six, which ends with two short but sharp climbs of the Mur de Bretagne in north-western Brittany.
Seven years ago, Cadel Evans won stage four at Mur de Bretagne on the way to becoming the first Australian Tour de France champion.
"We were right up at the front for most of the stage and I wasn't even aware that there had been crashes," Porte said.
"It was a nice day overall.
"Tomorrow (stage five) is a hard stage but it is more of a positioning battle.
"It's not an easy stage by any means but, I think stage six will be more of a test for me."
Porte is 14th overall at 51 seconds.
After losing time amid the crash chaos of the first two stages, Porte shot up the general classification when BMC dominated the team time trial on stage three.
After winning the opening stage, Gaviria (Quick-Step) took out a three-rider sprint at the end of the 195km-fourth stage from La Baule to Sarzeau.
The Colombian beat Slovakian three-time world champion Peter Sagan (Bora-Hansgrohe), while German sprint ace Andre Greipel (Lotto Soudal) faded to third after hitting out first.
"We wanted to wait to the last moment to launch but it was too hard. I'm really happy anyway," Gaviria said.
Sagan's second place meant the Slovakian retained the green jersey ahead of Gaviria.
"He's faster than me but it's ok," Sagan said candidly.
Wednesday's fifth stage is a 204.5km lumpy ride from Lorient to Quimper that should favour one-day classics specialists such as Van Avermaet.