West Yorkshire Police in northern England confirmed that the 25-year-old forward was 'arrested and questioned in connection with a serious sexual assault in a Leeds nightclub on January 14'.
However, Robinho's spokesman Chris Nathaniel claims that the Brazilian was only being summoned as part of an investigation.
"We can confirm that Robinho met the police today, as pre-arranged and as part of a criminal investigation," Nathaniel said in a statement on Robinho's personal website.
"He strenuously denies any allegation of wrongdoing or criminality and is happy to cooperate with the police if required further."
Apart from the fresh case, Robinho is poised to be fined by City for walking out of the team's training camp in Spain without permission a few days ago.
The British record-signing cited a 'family issue' as a reason for his sudden departure, but City boss Mark Hughes insisted there will be action against him.