The politician told MPs on Thursday that he was not “sufficiently alert” to the power imbalances between him and his employee.
He added he recognised his behaviour could well impact on “someone who is vulnerable whether or not that is known”.
“I made mistakes,” Vaughan continued.
The 36-page report said it took account of the impact of what happened on the complainant, who has a right to anonymity.
She said she was left feeling stressed, exhausted and offended, it adds.
The report also stated that Vaughan had “expressed genuine and thoughtful remorse”.
He should be required to make an “unreserved apology” to the complainant and the House by way of a personal statement in the House of Commons Chamber, it continued.
“We consider that this achieves the appropriate balance and clear messaging required regarding the behaviour expected of MPs,” the report said.
Vaughan added he had undertaken further training as a result of the incident.
Follow BBC Kent on Facebook, external, on X, external, and on Instagram, external and listen to BBC Radio Kent on Sounds. Send your story ideas to southeasttoday@bbc.co.uk, external or WhatsApp us on 08081 002250.
