A cell of Islamic State group supporters planning an attack in France was full of "lost, frustrated, suicidal, easily manipulated youths" and knew little of Islam, according to a French journalist who infiltrated the gang.

Said Ramai, an assumed named, said he "easily" contacted the "Soldiers of Allah" on Facebook and joined for six months before leaving in January.

He filmed meetings with a hidden camera as they plotted to attack a night club, the footage of which was broadcast on Monday in the documentary, "Allah’s Soldiers".

The cell consisted of 10 members and was led by a 20-year-old French-Turkish man called Oussama who, according to the documentary, was once a Satanist and an alcoholic who had been jailed for five months in France after trying to join IS in Syria.

"My goal was to understand what was going on inside their heads,” Ramai told the AFP news agency in comments reported on Monday.

"One of the main lessons was that I never saw any Islam. No will to improve the world. Only lost, frustrated, suicidal, easily manipulated youths.

"They are youngsters who are looking for something and that is what they found."

The documentary shows how Ramai was brought into the group with a promise of a "path to paradise", adding: “Our women are waiting for us there, with angels as servants. You will have a palace, a winged horse of gold and rubies.”

Footage shows Oussama saying his group could attack a military base, "when they are eating, they are all lined up... ta-ta-ta-ta-ta".

He also fantasises about attacking journalists: “Like they did to Charlie [Hebdo]. You must strike them at the heart. Take them by surprise. They aren't well-protected. The French must die by the thousands.”

Another clip shows a member of the group discussing using a rocket launcher to shoot down a plane landing at Paris–Le Bourget airport and "traumatise France for a century".

Meetings were held in Chateauroux and Orleans in central France. The group also communicated through the encrypted messaging service, Telegram.

The actual orders for the group's plot, an attack on a night club, came from a man known as Abou Suleiman, who had travelled to the IS "capital" of Raqqa in Syria. Ramai received them at a rail station in a handwritten letter delivered by a woman wearing a veil.

Ramzi received his hand-written orders from a woman (Canal+) The letter said he should shoot “until death” and then set off a suicide vest after police arrived.

He had already received orders on constructing his suicide vest.

Oussama and other members of the cell were arrested in December and January. Ramai said he got out of the group after receiving a message that he was "done for".