France has about 1,500 soldiers in Afghanistan
French President Nicolas Sarkozy has said France will send more troops to bolster Nato's mission in Afghanistan, subject to certain conditions.
Mr Sarkozy, who is on a state visit to Britain, said he would make the offer at next week's Nato summit in the Romanian capital, Bucharest.
Britain and the US have frequently called on other Nato members to send more soldiers to fight the Taleban.
The Nato-led force, Isaf, currently has over 43,000 personnel in Afghanistan.
In a speech to the British parliament in London, Mr Sarkozy said the Taleban could not be allowed to regain power.
"In Afghanistan something essential is being played out," he said.
"France has proposed a strategy to its allies in the Atlantic alliance to enable the Afghan people and their legitimate government to build peace.
"If these proposals are accepted, during the summit in Bucharest, France will propose reinforcing its military presence."
The BBC's political correspondent, Jon Devitt, says Mr Sarkozy wants guarantees from the alliance that Afghans will be given more responsibility, and that non-military aspects of the mission will be better co-ordinated.
He did not say how many soldiers he was thinking of sending - according to Nato figures, France currently has 1,515 soldiers in Afghanistan.
The BBC's diplomatic correspondent, Jonathan Marcus, says there have always been suspicions in London and Washington that France wants to undermine Nato and the trans-Atlantic partnership, but, he says, President Sarkozy is in the process of changing that impression.