Two spectators who threw beer and objects at Mathieu van der Poel in two cycling classics have been identified and face police questioning, a Belgian newspaper reported on Tuesday.
A fan who threw beer at the Dutch cyclist on his way to victory in the Tour of Flanders on March 31 will face legal proceedings for "assault and battery", La Derniere Heure reported.
Contacted by AFP, the local public prosecutor's office did not confirm the report.
Last week race boss Thomas Van der Spiegel said that "civil proceedings will be initiated when the beer throwers are identified".
Van der Poel won the Tour of Flanders, the second of the season's five one-day 'monuments' by one minute and two seconds.
A week later, he was even more dominant as he won Paris-Roubaix, the third monument, by exactly three minutes even though he was again the target of beer, abuse, insulting gestures and a hat thrown at his wheel on a cobbled section of the race.
La Derniere Heure said journalists in the Netherlands had reviewed film and identified the woman who threw a hat.
It reported that she is due to be interviewed by the French police this week.
"I felt that I had been hit by something white," said Van der Poel after the race.
"Apparently not everyone likes me riding in the lead," he said. "But I don't care. These people who throw beer at me are feeling a certain frustration, I think. But I don't want to worry about that."
In December, Van der Poel was fined for spitting at a group of abusive fans as he won a UCI Cyclocross World Cup race in Hulst in the Netherlands.