Police discovered two gas cylinders in the hallway of a building in the city’s western 16th district in the early hours of Saturday morning and two others on the pavement outside.
A mobile phone attached to the cylinders is being investigated as a possible detonator, a security source told AFP late Monday.
Speaking to Franceinfo radio on Tuesday, Interior Minister Gerard Collomb revealed that one of the arrested men was on a police terror watchlist.
“That shows that the threat level in France is extremely high,” the minister, who said the incident and a knife attack in Marseille on Sunday that left two women dead underlined the importance of a tough new security law, said.
French lawmakers in the lower house of parliament are set to vote Tuesday on a new counter-terrorism law that rights groups and UN experts have criticised for giving too much power to police and local government officials.
In Saturday’s incident, a resident alerted police after finding two gas cylinders about 4:30am in his building in the Porte d’Auteuil neighbourhood, a source close to the probe said.
Police then found another two cylinders outside the building.
A total of 241 people have been killed in a wave of jihadist attacks in France since 2015.
On September 12, Mr Collomb said 12 planned attacks had been foiled since the beginning of the year.
Three suspected women jihadists were arrested in September last year after the discovery of gas cylinders in a car near Paris’s Notre Dame Cathedral.