The Taliban said it had attacked the troops and blown up several vehicles.
Mullah Zaeef, a former Taliban ambassador to Pakistan, and former inmate of Guantanamo Bay, told Al Jazeera that the US-backed government of Afghanistan has lost control of key areas of the country to the Taliban.
Zaeef said that the government's position is "weak" and that the Taliban is gaining strength.
Zaeef said Sarkozy is visiting because of the unexpectedly "highy casualty" rate and because the EU is increasingly concerned about Taliban control.
Sarkozy went to the camp hospital and spoke to 10 of the wounded and other paratroopers who had been engaged in the fighting.
He was due to hold talks with Michel Stollsteiner, a French general who is head of Isaf troops serving in and around Kabul.
He also met Hamid Karzai, the Afghan president.
Sarkozy said before he left France on Tuesday that his visit was to show the troops that "France is on their side".
"In its struggle against terrorism, France has just been hard hit," Sarkozy said.
Sarkozy has insisted that France will not be deterred from its mission in Afghanistan, despite domestic opposition to the military involvement.
About 3,000 soldiers serve in the Isaf - made up of 53,000 troops from nearly 40 nations.
The deaths bring to 176 the number of international soldiers killed in Afghanistan this year.
Twenty-three French troops have now been killed in action or in accidents in Afghanistan since French soldiers were sent in 2002.
Sarkozy, who paid a brief visit to Afghanistan in December, has pushed for an expansion in France's military role.
He announced French reinforcements to Afghanistan at a Nato summit in April - drawing criticism from left-wing politicians who saw the move as a sign of French alignment with US policy.