A man arrested last week in the west of Paris was planning "an imminent act of terror," Paris prosecutor François Molins told reporters on Wednesday.
Reda Kriket, a 32-year-old French national, was charged with being part of a terrorist group, forging official documents, possessing weapons, and making explosives.
Molins said that investigators searching the suspect's apartment in the Paris suburb of Argenteuil had found an arsenal of weapons and explosives that he described as "unprecedented in its size."
"Everything leads us to believe that the discovery of this cache helped avoid the execution of an act of extreme violence by a terrorist network ready to act," Molins remarked, adding that investigators had not identified a "precise target" for an attack.
Among the weapons retrieved from the fourth floor apartment were five Kalashnikov rifles, a submachine gun, and seven handguns. Police investigators also found industrial grade explosives, tear gas canisters, fake passports, and brand new cellphones.
The apartment, which Kriket had been renting under a fake name since summer 2015, was also used to stock TATP, an explosive that was used in the Paris attacks and also recovered during a March 22 raid on a terrorist hideout in Brussels.
Officers found two computers containing documents about jihadist networks and instructions on how to make homemade bombs at the apartment. They also found a book called The Modern Laboratory.
Kriket was already known to the police, having accumulated 10 criminal convictions, including for robbery and violent offenses, which he did not specify.
In 2015, Belgian authorities convicted Kriket in absentia to 10 years in prison for his involvement with a jihadist recruitment network known as the Zerkani network.
Abdelhamid Abaaoud, one of the gunmen who carried out the November 13 Paris attacks and who was later killed in a police raid in Saint-Denis, was also sentenced for his role in the network.
Molins said that police in the Dutch city of Rotterdam had also arrested Kriket's accomplice Anis Bahri on Sunday, following a request by France. Bahri and Kriket are suspected of traveling together to Syria in late 2014 or early 2015.
Bahri also has prior convictions, and was sentenced for robbery in 2006 and armed robbery in 2008.
Kriket has denied the charges against him, claiming he rented the apartment for an acquaintance whose name he refused to reveal. The acquaintance and another individual, he told investigators, had used the apartment to stock weapons and make bombs last year.
Kriket also told investigators that he was not a terrorist, according to Molins, and that he had been planning on selling the fake passports on the black market.
When questioned about his relationship to Barhi, Kriket said that he had recently renewed ties with him, and admitted to housing him in the apartment in Argenteuil.
Correction: An earlier version of this story misplaced the city of Rotterdam in Germany — Rotterdam is in fact in the Netherlands. The story has been amended.