A spectator who is  suspected of causing a mass crash on the opening day of the Tour de France has been arrested, French judicial officials said on Wednesday.

The female suspect, a 30-year-old French national, is in custody after handing herself in to the police.

Brest prosecutor Camille Miansoni confirmed the arrest on Wednesday.

The woman brandished a cardboard sign on the roadside during the Brest to Landerneau stages of the Tour de France.

But she had her back turned towards the speeding peloton and collided with German rider Tony Martin.

Martin tumbled to the ground, sparking the mass crash and causing the race to be held up for more than five minutes.

Another huge pile-up occurred on narrow roads on Monday, leading the Tour de France riders to hold a minute-long silent protest for safer racing conditions.

Organizers and the International Cycling Union (UCI) have been targeted by some riders who demand larger roads.

But with the number of traffic islands, roundabouts and speed bumps having been multiplied by six over the past 25 years in France, those calls have been rebuffed thus far.

Wednesday’s fifth stage is a 27.2-kilometer (16.4-mile) individual time trial from Change to Laval.

The 2021 Tour de France is the 108th edition of the Tour de France, one of cycling's three grand tours. It ends on the Champs Elysees in Paris on July 18.

jf/sms (AP, AFP)