Chatham-Kent Police Service were made aware of the charges in November and asked Windsor police to do the investigation.
Constable Andrew Jaconelli has since been charged with one count of sexual assault, and one count of assault with a weapon in connection with an incident from November 2017.
He was off duty at the time.
He has also been charged with discreditable conduct under the Police Services Act.
Jaconelli made a brief court appearance on Friday and will appear again January 8th of 2019.
He was suspended from duty with pay on Friday