Five alleged accomplices in the Nice truck attack that killed 84 people have been charged with terror offences.
The news came after the Paris prosecutor said 31-year-old Mohamed Lahouaiej Bouhlel was helped by at least one other and appeared to have been plotting his July 14 attack for months.
Four men and one woman, aged between 22 and 40, have been detained, prosecutor Francois Molins said.
Three men, identified as Franco-Tunisians Ramzi A and Mohamed Oualid G, and a Tunisian named Chokri C, were charged as accomplices in "murder by a group with terror links".
An Albanian man named Artan and a French-Albanian woman identified as Enkeldja are suspected of providing Bouhlel with a pistol and were charged with "breaking the law on weapons in relation to a terrorist group".
Molins cited text messages, more than 1,000 phone calls and video of the aftermath of the attack recorded on the phone of one of the suspects.
Bouhlel and a 30-year-old French-Tunisian with no previous convictions had phoned each other 1,278 times in a year, Molins said.
A text message from the same man found on Bouhel's phone said: "I'm not Charlie; I'm happy. They have brought in the soldiers of Allah to finish the job."
The message was dated three days after the January 2015 massacre at Charlie Hebdo magazine in Paris, referring to the worldwide phrase of solidarity for the victims "Je suis Charlie (I'm Charlie)".
The same man filmed the bloody scene on the promenade hours after the attack.
Details about the investigation were released after France's interior minister Bernard Cazeneuve faced criticism over insufficient security despite the state of emergency in place since the Paris attacks last November.
Cazeneuve admitted, contradicting previous statements, that only local police who were more lightly armed were guarding the entrance to the Promenade des Anglais when Bouhlel drove his truck down it.
He then launched an internal police investigation into the handling of the Nice attack.
President Francois Hollande said the conclusions of that investigation will be known next week. He said any police "shortcomings" will be carefully addressed but defended French authorities' actions.