She accused him of isolating her during rehearsals and filming. Of grooming her for three years, when on Saturday afternoons he would touch her sexually. When it began, he was 36. She was 12.

Five years ago, the French actress Adèle Haenel shocked the country’s film world when she spoke out about the relationship she had with the director Christophe Ruggia. He had cast her as the lead actor in a 2002 film about an incestuous relationship.

On Monday, the case will go to court, marking the first major #MeToo case in France to proceed to trial. Mr. Ruggia, 59, is charged with aggravated sexual assault against a minor. If he is found guilty, he faces up to 10 years in prison as well as a fine of up to 150,000 euros, about $190,000.

Mr. Ruggia has repeatedly denied the allegations, saying that his relationship with Ms. Haenel was strictly platonic and that he never sexually harassed or touched her inappropriately. His lawyer Fanny Colin has refused to speak publicly before the trial, but has said that Mr. Ruggia intends to plead not guilty.

After Ms. Haenel first told her story to the French investigative outlet Mediapart in 2019, it inspired heated conversations about the country’s film industry and sex with minors, and how the French justice system treats sexual abuse complaints.

At the time, Ms. Haenel was a rising star, praised for fierce yet sensitive performances that had earned her two Césars — the French equivalent of the Oscars. In the United States she rose to fame with “Portrait of a Lady on Fire,” her final role before she announced her decision to boycott the industry.