The robbers stole what they believed to be a €3 million (R49 million) painting from the Santa Maria Maddalena church in Castelnuovo Magra, northern Italy.
Police in Castelnuovo Magra, a small town in Liguria, said they had uncovered a plot to steal the painting from Santa Maria Maddalena church - and so set a trap a month ago, according to Italian media.
Hours later, Italian police revealed they had heard rumours of the planned heist - and installed cameras to catch the thieves in the act.
Thieves used a hammer to smash open its display case and made off in a auto.More news: Raonic Beats Kecmanovic To Reach Indian Wells Semi-final
The surveillance footage of the raid is now being carefully studied and investigators are chasing down those responsible.
The town's mayor, Daniele Montebello, who police had informed about the operation, played along with the deception after the robbery, telling the Italian news agency ANSA: "It is a work of inestimable value, a hard blow for our community".
Montebello admitted on Wednesday night that the stolen painting had been a fake.
The country is a popular destination for art thieves, with half of the artefacts stolen in 2016 being held in churches.More news: Nigel Farage to lead 400km Brexit protest march
He also thanked members of the church who had "noticed that the one on display was not the original, but did not reveal the secret".
The painting - donated to the church by a wealthy family in the 19th century - was stolen almost 40 years ago. During World War Two it had to be hidden from Nazi soldiers, who were infamously prone to helping themselves to other people's cultural treasures; while art thieves actually managed to make off with the painting in 1981, before being tracked down and returned by police a few months later.
The 26in by 17in canvas is a copy of a work by his father.More news: Southgate names newly-eligible Rice in England squad