Olivia Grenon, 22, was responsible for a prolonged period of deceptive conduct in 2012, using lies and fraudulent documents to cheat Canberrans of their money.

She lied numerous times in attempts to get car loans, creating fake payslips for a French-Australian pre-school, and falsified tax invoices and a driver's licence.

In September last year, Grenon managed to obtain finance for a car.

She sold the car on to an unsuspecting Canberra man for tens of thousands of dollars, telling him there was nothing owing on the vehicle.

Grenon also advertised an iPhone for sale on the online classifieds site Gumtree.

She “sold” the iPhone to a string of customers, taking their money, but never sending the promised goods.

She was eventually arrested in December last year, but told police that she had an identical twin sister in Tuggeranong.

Checks with immigration authorities proved that to be another lie and Grenon was charged with a string of fraud offences.

In the ACT Supreme Court on Monday, Acting Chief Justice Richard Refshauge said the French national appeared unable to separate fact from fiction.

Justice Refshauge said she had an emotional disorder and a personality marked by “glib and superficial emotional traits”.

He said she experienced a chaotic childhood in France, which had forced her to use her wits to survive.

Justice Refshauge said that led to her deceptive behaviour, and had created an emotional need to be liked and accepted by others.

Grenon had told varying stories about her early life to the authors of numerous mental health and sentencing reports.

She told the most recent author she was afraid she would be found out as a fake if she stopped lying.

The court heard Grenon previously presented to Calvary and Canberra hospitals. She would complain of symptoms, but medical staff were unable to find anything wrong with her.

Justice Refshauge said it was possible she was unconsciously seeking the attention of others by complaining of her symptoms.

He told Grenon that she must have known what she was doing was criminal, and said her behaviour was a waste of time.

“I hope this has been a lesson for you,” Justice Refshauge said.

“You're obviously a very intelligent and talented young woman."

Grenon was sentenced to 25 months in prison, but will be eligible for parole in December, four days before Christmas.

It is likely she will be deported upon release.