Hadush Kebatu was flown back to his home country on Tuesday night and arrived on Wednesday morning with no right to return to Britain, the Home Office had said.
He was forcibly removed with a team of five escorts on the flight.
It is understood he was given the discretionary payment by officials in the removals team as an alternative to a slower and more expensive process, which would have included detention, a new flight and a potential for legal challenge.
The Ethiopian national had been wrongly freed from HMP Chelmsford on Friday morning instead of being sent to an immigration detention centre, triggering a two-day manhunt.
Home Secretary Shabana Mahmood said she shared the public’s anger over his release and had “pulled every lever” to remove Kebatu from British soil, but opposition MPs said his deportation did not excuse the fiasco.
Ministers did not approve the payment, which was an operational decision, it is understood.
It is believed that cancelling the flight alone would have cost thousands of pounds.
Kebatu had been living at the Bell Hotel in Epping, Essex, when he sexually assaulted a 14-year-old girl and a woman, sparking a wave of protests outside the accommodation used to house asylum seekers.
The incident has prompted an independent inquiry to find out what went wrong and a prison officer has been suspended while the probe is carried out.
Prisons have also been told to start a series of enhanced checks before inmates are released after the mistake.
Ms Mahmood said: “Last week’s blunder should never have happened, and I share the public’s anger that it did. I would like to thank the police for rapidly bringing Mr Kebatu into custody and the public for their vigilance.
“I have pulled every lever to deport Mr Kebatu and remove him off British soil. I am pleased to confirm this vile child sex offender has been deported. Our streets are safer because of it.
“If you come to this country and commit crimes, we will remove you.”
It is understood that Kebatu, who crossed the Channel in a small boat to enter the UK on June 29, left prison on Friday with some personal money but did not receive a discharge grant.
His trial heard he had made inappropriate comments to a 14-year-old girl before trying to kiss her on July 7, just eight days after his arrival in the UK.
The following day, he sexually assaulted a woman by attempting to kiss her, placing his hand on her leg, and telling her she was “pretty”.
He denied the charges against him but was found guilty of five offences and sentenced in September to 12 months in custody, including the time he had already time in jail awaiting his trial.
The court heard it was his “firm wish” to leave the UK.
