Five men arrested last weekend in raids in France were planning a terror attack next Thursday in the Paris area, the city’s chief prosecutor says.
Francois Molins said the suspects were receiving orders via encrypted mobile apps from a commander of the so-called Islamic State based in Iraq or Syria.
The raids, in Strasbourg and Marseille, also turned up automatic weapons.
The five are to be placed under judicial investigation on suspicion of terror crimes.
Mr Molins said investigators had not established the target of the planned attack, but he said GPS co-ordinates were found on a USB stick.
Possible targets included the Paris law courts, the nearby headquarters of the judicial police, the Christmas market on the Champs-Elysees and the Disneyland theme-park east of the city, French media say.
The four arrested in the eastern city of Strasbourg – said to be in their 30s – are all French nationals of North African origin. Two of them had travelled to Syria last year, investigators are quoted as saying.
The fifth man, a Moroccan arrested in the southern city of Marseille, did not know the other four but was receiving orders from the same source, they say.
According to the prosecutor, the group had been under surveillance for several months, and police moved in to arrest them to avert imminent bloodshed.
France remains under a state of emergency following the attacks in Paris in November 2015 that killed 130 people.