Alain Vidalies told reporters that the contract, initially valued at USD 25 billion, is subject to approval from the US government's Office of Foreign Assets Control (OFAC) and talks are planned next week.
The deal would be by far the biggest commercial contract signed since Iran and world powers implemented an agreement on Tehran's nuclear programme that saw crippling sanctions lifted in January.
"We are in a very advanced stage of negotiations since the meetings should be held next week to finalise the decision," said Vidalies, who arrived Sunday on the first Air France flight to Iran in eight years.
Iran agreed to buy the medium- and long-haul aircraft when President Hassan Rouhani visited France in January, just days after the nuclear deal lifted sanctions.
Western manufacturers were barred for nearly two decades from selling aircraft or equipment and spare parts to Iranian companies.
That embargo was blamed for crippling Iran's aviation industry. Its civil aviation fleet has 140 aircraft, with an average age of around 20 years, and many are in desperate need of replacement.
