The Harlequins scrum-half was arrested by West Yorkshire Police, after reports of the incident in the early hours of Sunday, March 4, PA said.
In a statement, the club said: "Danny Care was asked to report to West Yorkshire Police in Leeds to answer further questions about the incident that took place in the city on March 3.
"On March 15, Danny attended Leeds Police Station voluntarily by appointment to assist the police with their inquiries. He denies the allegations made against him. Harlequins are fully aware of all the facts and will continue to support Danny as he addresses this situation."
Care, who denies the allegations, has already received a police caution for being drunk and disorderly on the same night, after being arrested when caught urinating outside of a hotel in the city.
"A 25-year-old man, from Surrey, was arrested in connection with a sexual assault on a woman in Leeds in the early hours of Sunday, March 4," a West Yorkshire Police spokesman said. "He has been bailed pending further inquiries."
Bale has since been bailed by police. In January, he was handed a 16-month driving ban and fined £3,100 after pleading guilty to drink driving during the early hours of New Year's Day.
> More Showbiz news