Police said she was injected with an anaesthetic when she arrived at a Milan apartment, put inside a suitcase and taken in the boot of a vehicle to a village in the Piedmont region.
The woman, 20, whose identity has not been revealed, was held prisoner for a week after being drugged with ketamine, authorities said.
The kidnapper was captured by police as he was accompanying the model to the British Consulate in Milan, according to the Telegraph.
The woman was kept handcuffed to furniture but was freed and taken to the British embassy in Milan, despite the ransom not being paid.
He had told the model that he could not go on holding her because she was a mother of a young child and such abductions were prohibited by "Black Death", a nefarious web-based group he claimed to belong to.
Police say it is unclear whether he had really abducted the victims or invented them for the auction.
Officials have released a mugshot of the suspect, named as 30-year-old Lukasz Pawel Herba.
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It has been reported that the captor demanded £50,000 upon the woman's release and threatened to kill her if she told police about the incident.
The woman in her 20s, who has not been named, allegedly flew over to Milan from Paris to attend the shoot after being told to by her United Kingdom agent.
The unnamed suspect faced pre-trial before magistrate Anna Magelli yesterday.
Police found a small bedroom at the property, but it is unclear whether it was used by the model or the kidnapper.
The kidnappers then started blackmailing her modelling agency, demanding USD$300,000 (A$377,000) in ransom, Italian authorities said.
It is understood the police investigation involved reconstructing the kidnapping scene and studying CCTV footage from the area.
But reports in La Stampa alleged Herba had contacted the model's agent and demanded the same £270,000 price for her freedom.