Homemade explosives ready for use were found on Wednesday in an unoccupied flat near Paris, judicial sources said, according to AFP.
Gas canisters and electric wiring were also found in the flat in Villejuif, a suburb south of the French capital. Two men were arrested nearby, the sources said.
The explosive, known by the initials TATP, is notoriously used by the Islamic State (ISIS) jihadist group, which has repeatedly targeted France in recent years.
Police also found ingredients that can be used to produce TATP as well as papers written in Arabic, according to the AFP report.
Anti-terror prosecutors have opened an investigation, sources close to the probe said. One of the two arrested men, aged 36 and 47, is the owner of the flat, they added.
Paris police said a man who works at the apartment block had alerted police to “suspect items” in the apartment.
The ISIS cell that was behind twin attacks that claimed 16 lives in Barcelona and Cambrils, Spain, last month had been preparing TATP, the news agency noted.
Investigators probing a house that been wrecked by an explosion found acetone and other TATP ingredients, as well as 120 butane canisters and detonators.
The car used by the assailants in Cambrils had been in the Paris area less than a week before the attacks, but a source close to the probe stressed, “At this stage there is nothing to link the discovery of these items (in Villejuif) to the Catalonia cell.”
France remains under a state of emergency which has been in place since ISIS terrorists carried out an attack in Paris in November 2015, leaving 130 people dead.
Since that attack and last year’s truck attack in Nice that killed 86, France has suffered a string of smaller assaults mainly targeting security forces.
Last month, a man armed with a knife attempted to enter the Eiffel Tower and attack a soldier.
As he made his way through the security guards, he yelled, "Allahu Akbar!" Some of the soldiers guarding the tower immediately ordered the suspect to drop his weapons, and he did so without attacking anyone.
In February, a knife-wielding terrorist attacked French soldiers at the Louvre.