You need a visa for Iran if you have a French passport
Visa options for Iran
Electronic visitor visa
Travellers need a visa to visit Iran for Business or Tourism. Travellers must complete the visa application online, give a hard copy of the Submission Notice at the border crossing, and pay the visa fees in euros at the airport. A visa on arrival is obtained at the port of entry before reaching immigration. Travellers can purchase the visa at the airport upon arrival in Iran. For all other visas, visit the government site.