The race leader slowed down to allow the stragglers to catch up and despite the spectacular tangle only one rider, Germany's Jasha Sutterlin of DSM, has so far had to pull out due to the accident.
Italian champion Sonny Colbrelli and Dutch rider Wout van Aert, who ran over Martin before falling head over heels, had both been amongst the favourites to win the first stage hilltop finish but were both badly delayed.Welsh Ineos rider Geraint Thomas and defending champion Tadej Pogacar appeared unhurt, although last year's runner-up Primoz Roglic looked to have fallen heavily.
Hordes of unmasked fans decked out in red-and-white polka dot caps and shirts lined the narrow Brittany country lanes for the 197km stage as France eases its COVID-19 restrictions.
The bikers when they get up after having lost their position unnecessarily