Thieves who stole a mural bystreet artist Banksy on an emergency exit door of the Bataclan concert hall in Paris used a crowbar and angle grinder to prise it free in a crime that lasted just minutes, a French court heard.

The work depicting a veiled and mournful figure is thought to have been a tribute to victims of the Islamist militant attacks against the Bataclan and other entertainment venues in Paris in 2015.

Seven Frenchmen and an Italian went on trial in Paris for the theft today.

Defence lawyers for some of the men framed the theft as a case of small-time crooks who ended up with a more troublesome object on their hands than they had anticipated.

The lawyer for Franck Grillet-Aubert, one of the three men accused of prising the door from its fittings, said his client had no idea what he was stealing.

"It's simple. Since the beginning of this case he has said he was there because he knew how to cut doors.

"It's as stupid as that. He was asked to do that, he did it, he put the door in the van and went home," the lawyer told reporters outside the court.

The trio were captured on surveillance camera but identified after police tracked their phones following a separate theft.

They have admitted theft but dispute who was behind the crime.

An Italian Carabiniere poses beside the mural after it was recovered in Italy

Banksy, who is based in Britain and whose real identity is unknown, has become one of the most well-known personalities of the modern art scene with a series of works in public places that combine street art techniques with topical themes.

He spray-painted the mural on the Bataclan door in 2018. It was stolen in January 2019 and found the following year in a farmhouse by Italian police.

Ninety people were killed inside the Bataclan during the coordinated attacks across Paris by Islamist gunmen and suicide bombers that caused 130 fatalities in total.

"Many people in the (Bataclan) audience escaped through this emergency door. It lived, heard and saw the whole massacre," French Ambassador to Rome Christian Masset said at the time the door was found in Italy.