The spectator who sent cyclist Tony Martin and, consequently, a large part of the Tour de France peloton crashing in the opening stage of the race has been arrested, according to multiple reports.

BFM television, citing multiple police sources, reported that the woman had been taken in custody in Brittany, the northwest French region where the Tour de France, the world's biggest cycling event, held its first four stages.

RTL is reporting that she is facing a fine of €1,500.

On Saturday, Martin was sent tumbling when he rode straight into a cardboard sign being held out by the woman, who was looking the other way at a television camera, creating chaos with 47 kilometers (29.2 miles) left in the stage.

A huge crash at #TDF2021 this morning was caused when a spectator held out a sign and struck a rider.

Jasha Sütterlin was forced to withdraw from the race due to an injury sustained in the crash, according to @LeTour. pic.twitter.com/XCcEjHRAGp

— NBC Sports (@NBCSports) June 26, 2021

The Tour has cautioned fans to "respect the safety of the riders'' and not to "risk everything for a photo or to get on television!''

Tour organizers said on Saturday that they planned to sue the woman.

"We are suing this woman who behaved so badly," Pierre-Yves Thouault, the Tour's deputy director, said, according to AFP. "We are doing this so that the tiny minority of people who do this don't spoil the show for everyone."

Another huge pileup occurred in a nervy finale on narrow roads on Monday, leading the Tour de France riders to put their collective foot down at the beginning of the fourth stage on Tuesday -- literally -- bringing the race to a halt for about a minute in a silent protest for safer racing conditions after the crashes.

The brutal scenes prompted veteran sports director Marc Madiot from the Groupama FDJ team to lash out over the lack of safety on the road.

"Tonight, I don't want to see my son become a professional rider,'' Madiot said Monday at the finish in the town of Pontivy. "My wife does not want to see my son on a bike. It's been years that we are talking about [safety]; we need to find solutions. It's not bike racing anymore. One day there will be dead people.''

The last rider to die on the Tour was Fabio Casartelli, an Italian on the then-Motorola team of Lance Armstrong who crashed on the descent of the Portet d'Aspet pass in 1995.

Reuters and The Associated Press contributed to this report.