A chance alert by a local tradesman has exposed a terror-linked bomb plot to target banks, French Interior Minister Gérard Collomb has revealed.
Police were called on Wednesday to a flat in the southern Paris suburb of Villejuif, where they found 100g of TATP explosives and chemicals.
Three men have been arrested.
The interior minister said the suspects had denied any terrorist motives but he added that they had been in phone contact with people in Syria.
“They wanted to blow up banks with the TATP, but what we’re seeing is that they were linked to terrorists, so it’s more in that direction that we have to look,” he told FranceInfo TV.
TATP (triacetone triperoxide) has been widely used in jihadist attacks because it is relatively easy to produce.
The explosives would have been used to target counters inside the banks for cash, Mr Collomb added.
The alarm was raised by a man working at the block of flats on Wednesday morning. When he spotted suspicious objects through the window he called police, who discovered a type of bomb factory inside. Gas canisters and electrical wiring were also found.
Two suspects, aged 36 and 47 and of North African origin, were quickly arrested in a neighbouring area, and a third man was detained overnight. Mr Collomb told French TV they were all French nationals who were not previously known to the authorities.
France has suffered a spate of attacks in recent years. Jihadists who attacked Paris in 2015 also used TATP.
More recently traces of it were found last month in the rubble of a house in north-eastern Spain on the eve of the Barcelona attack. Catalan police believe the jihadists had been planning to use explosives from the house as part of the Barcelona plot.
Mr Collomb declined to speculate on whether the latest discovery was linked to Barcelona.
However, investigators have been trying to find out why attacker Younes Abouyaaqoub had driven to the Paris area days before the attacks.
He stayed at a hotel in the Malakoff area a few kilometres to the north-east of Villejuif.