French President Francois Hollande has described the US-Russia deal on Syria's chemical weapons as an "important step" towards the much bigger goal of a political solution to the civil war.
But in a TV address Mr Hollande said: "The military option must remain; otherwise there will be no pressure.
Mr Hollande said a vote on a new UN Security Council resolution on Syria could be agreed by the end of the week.
On Monday he will meet US Secretary of State John Kerry to discuss the issue.
The president said sanctions will be enforced to coerce Syria into dismantling or handing over its chemical weapons if Damascus fails to comply.
"It is necessary to include the threat of sanctions if the agreement and the aims of the Security Council resolution aren't carried out,'' he said.
"But the next step has to be finding a political solution to the Syrian crisis."'Too hawkish'
On Monday Mr Hollande and his Foreign Minister Laurent Fabius will meet Mr Kerry and British Foreign Secretary William Hague to discuss the wording of the new draft resolution.
The BBC's Christian Fraser in Paris says that France takes a hawkish position on Syria - and a majority of French people think it is too hawkish.