Also, the first visit of Rouhani to Paris in 17 years aimed to further cement political dialogue despite disagreements mainly over the Syrian conflict.
French president Francois Hollande and his Iranian counterpart held "restraint discussion" over the situation in the conflict-ravaged Arab country.
The meeting would represent an opportunity to invite Tehran to "play a constructive role in resolving the crisis" and help to end the diplomatic row between Iran and Saudi Arabia, the Elysee added.
At a Franco-Iranian business forum, Rouhani on Thursday called on both parties "to forget past differences and start anew."
Accompanied with a delegation of 120 business leaders, Iranian president told local media that Iran is opening its doors to French investors.
In this context, French and Iranian officials are working on a raft of accords mainly on tourism, industry, agriculture, finances, environment, health and telecommunication.
"Iran has considerable needs in the areas of infrastructure, construction of networks, automotive industry, air and rail transport, which are areas in which French companies are excelling," the Elysee said, estimating the potential gains of local firms in Tehran at more of 10 million euros (10.91 million US dollars).
At a gathering of main companies from the two countries, French Prime Minister Manuel Valls announced a joint venture between France leading car maker PSA and Iran's Khodro to produce 400,000 vehicle annually by 2020.
Agreement to order hundreds of Airbus aircraft by the Islamic republic is also due to be announced.