Detective Constable Craig Winkless is to face a misconduct hearing following the allegations relating to an incident in April 2019.
A statement on the South Yorkshire Police website reads: "On April 25, 2019, DC Winkless visited witness A at her home address as part of his duties, whilst investigating an allegation of assault by her ex-partner.
"Whilst at the address it is alleged that the officer made inappropriate and unprofessional sexualised comments and it is further alleged that he also inappropriately touched witness A in a sexualised manner.
"Based on the information available at this time the conduct described above, if proved or admitted, has been assessed as amounting to Gross Misconduct, in relation to breaches of the Standards of Professional Behaviour relating to Honesty and Integrity, Authority, Respect and Courtesy, Duties and Responsibilities and Discreditable Conduct."
The misconduct hearing is scheduled to take place on Monday, April 26, and expected to run for five days.