Gunmen snatched the group as they were travelling about 60km from the Afghan capital, a French journalist working with them said.
Criminal groups and Taliban insurgents have kidnapped several dozen foreigners, many of them journalists, since the 2001 US-led invasion ousted the Taliban regime in Kabul, sparking a nine-year insurgency.
"The two journalists, accompanied by their Afghan translator, and the translator's brother and cousin, were kidnapped on the road between Surobi and Tagab," their French colleague said.
She blamed the kidnapping on the Taliban, saying they had laid an ambush for the group in Kapisa province.
French defence minister Herve Morin, who was visiting French troops in Afghanistan to mark the New Year, confirmed only that the journalists had been missing since Wednesday.
"We can't rule out any hypothesis and are doing everything to make contact with them."
The journalists' employer, public broadcaster France Televisions, did not formally confirm their abduction.
"We have had no news of them for 48 hours," said Paul Nahon, director of documentaries. The journalist and cameraman had been working on a documentary for about two weeks, he said.
French troops deployed in Kapisa have launched a manhunt for the five.