France will do "everything" to keep Greece in the eurozone, French Prime Minister Manuel Valls has said.
"France is convinced that we can't take the risk of Greece leaving the eurozone," Valls told French radio on Tuesday morning.
The main suspect in the beheading of a businessman took a "selfie" with the slain victim and sent the image to a Canadian mobile phone number, officials said.
French investigators were working to determine the recipient's identity, but were not able to confirm reports that it was an unspecified person now in Syria, where the radical Islamic State group has seized territory.
The main suspect Yassine Salhi, a truck driver with a history of radical Islamic ties, as well as his sister and wife remained in police custody in the city of Lyon, a day after he allegedly crashed a truck into a US-owned chemical warehouse and hung his employer's severed head on a factory gate, officials said.
One of the officials said the selfie was forwarded via WhatsApp to a phone number in Canada.
Four people have been arrested following a terrorist attack in which a man was decapitated, French authorities said.
Two men drove a car into a plant owned by an American gas company setting off two explosions.
ITV News' Rebecca Barry reports:
A firefighter seized the main suspect following the France terror attack in which a businessman was decapitated. The suspect, Yassine Salhi, was flagged in 2006 for suspected ties to radical Salafists, France's Interior minister Bernard Cazeneuve said.
Mr Cazeneuve said Salhi - a resident of the Lyon suburb of Saint-Priest who is in his 30s - had been known to intelligence services and was under surveillance from 2006 to 2008.
Officials said the decapitated man was the boss of a local transportation company that employed Salhi. One official said he was believed to have been killed before the attack on the factory and was not killed by the explosion.
Three people have been detained after a man was decapitated in a suspected Islamist terrorist attack at a chemical factory in Saint-Quentin-Fallavier near Lyon, southeastern France.
The man who was detained was Yassine Salhi, who is in his 30s and from the Lyon suburb of Saint-Priest, a police intelligence official confirmed. Two people were arrested at Salhi's apartment by security officials, with one said to be his wife.
President Francois Hollande has raised the security level in France to its highest possible point, following the terror attack near Lyon.
Hollande described the attack as "cowardly" and has promised that thousands of police officers will be deployed across France in order to improve security.
A source close to the investigation has told Reuters that the person who was found beheaded at a chemical factory in Saint-Quentin-Fallavier near Lyon, southeastern France was the manager of the man suspected of ramming their delivery vehicle into gas canisters there.
The source told Reuters that the two went together to the company site to make a delivery. The suspect is believed to have killed and decapitated his victim before then driving their vehicle into the premises, the source said.
The wife of terror attack suspect Yassin Salhi has been arrested, according to AFP.
She is the third person to be arrested following the attack at an Air Products factory close to Lyon on Friday.
French Prime Minister Manuel Valls has spoke of the "blind horror" terrorism has caused across the world on Friday.
"The blind horror and threat of terrorists spares no country. My thoughts are with the victim in Isere and the victims in Tunisia," Valls tweeted.
A woman claiming to be the wife of terror attack suspect Yacine Sali has told a French radio station she has no idea what has a happened.
Sali was arrested at the scene of the attack in the south of France, much to his wife's surprise.
I have no idea what's happened. Has he been arrested?
He didn't come back between midday and two o'clock, which is when I expect him back. My step sister told me to look at the TV and see the news and she was crying. I thought my heart was going to stop beating.
I know him he is my husband. We have a normal family life. He goes to work and comes home. He doesn't pick up the phone when I call, it goes to the answer machine.