Four French troops were killed and 17 others wounded in eastern Afghanistan after an Afghan National Army soldier opened fire on his international partners, causing suspension of French military operations in the country.
The incident happened in Tagab district of Kapisa province.
French President Nicolas Sarkozy on Friday confirmed that his country had lost 4 soldiers, adding that French military operations were suspended in Afghanistan.
"We are the Afghan people's friends, and we are Afghan people's allies, but I can't accept that Afghan soldiers could fire on French soldiers. If the security conditions are not clearly established, then the question of an anticipated withdrawal of the French army will be raised," Mr Sarkozy said.
Nato has also confirmed the deaths and added that one person has been detained in connection with the incident, but no details were provided.
Fifty eight Nato soldiers have been killed by their Afghan partners from May 2007 to May 2011 in 26 different incidents, Nato says.
Meanwhile, Nato says six of its soldiers were killed in a helicopter crash in the south of Afghanistan on Thursday. The cause of the crash is not yet clear and investigations are continuing, Nato added.
The deaths on Friday put the number of French soldiers killed in Afghanistan to 82 since 2001.
France has around 3,600 troops under the Nato mission in Afghanistan.