The 31-year-old French woman, whose identity is kept secret after being exposed to a stream of cyber-hatred, has already told the prosecutor that she is "ashamed of her stupidity" during the first stage of the French cycling classic in June.
The scandal occurred on a narrow road near the finish line in Landerneau in western France.
The woman stood with her back to the rushing cluster and held a sign with a greeting to relatives in Germany that she hoped the TV cameras would intercept.
Broke both arms
German Tony Martin drove into the woman, lost control and then dragged large parts of the field with him in the case.
Eight cyclists had to seek medical attention and several were forced to break the race, including the Spaniard Marc Soler who broke both arms.
The woman then fled the scene and remained hidden for four days before surrendering to police.
The trial began on Thursday.
Prosecutors demanded a four-month suspended prison sentence for the woman on the first day of the trial.
The woman herself told prosecutors that she was ashamed of what she had done and that it was a mistake.
She is accused of causing unintentional damage and endangering the safety of other people.
The French court will deliver its judgment on 9 December.
The organizer of the Tour de France considered suing the woman, but has chosen to back down to "calm the situation".
Symbolic damages
But the professional cyclists' organization CPA stands by its application and demands a symbolic compensation of 1 euro to send a message to supporters who behave dangerously during the stages.
- An athlete prepares for months for a "Grand Tour" and it is not acceptable that all work from the family, staff and team should be crushed in an instant in search of popularity, says chairman Gianni Bugno.
CLIP: Matej Mohoric won his second stage of this year's Tour de France (July 16)
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Stage winner Matej Mohoric showed what he thought of the police raid on Wednesday.
Photo: TT