The airline will appoint a "special unit" to replace those who do not want to fly to Tehran, he said.
"Any woman assigned to the Paris-Tehran flight who for reasons of personal choice would refuse to wear the headscarf upon leaving the plane will be reassigned to another destination, and thus will not be obliged to do this flight," human resources official Gilles Gateau told Europe 1 radio.
Air France is to resume on April 17 its Paris-to-Tehran service, which had been suspended since 2008 because of international sanctions against Iran over its nuclear ambitions.
Unions say company executives sent staff an internal memo regarding flights to Tehran saying that female cabin crew would be required to wear trousers on board with a loose fitting jacket and must cover their hair with a scarf when they leave the plane.
The headscarf rule is already in place when flying to certain destinations such as Saudi Arabia.
Unions, who held talks with the human resources chief on Monday, argue that an escape clause was already in place for flights to Conakry in Guinea during the Ebola crisis last year and for services to Tokyo following the 2011 Fukushima nuclear disaster.