Le Drian's trip comes at a critical point in diplomacy between Tehran and the west. His task is not an easy one.
The French foreign minister travelled to Tehran on Monday to talk about issues that have already been agreed upon. Or about issues that Tehran says are not up for discussion.
Take the 2015 nuclear agreement, which was dramatically limited Tehran's ability to enrich uranium. There have been 10 inspections by the International Atomic Energy Agency (IAEA) and each has concluded the same thing: Iran is sticking to its side of the deal.
The part of the equation that has changed is the occupant of the White House - Donald Trump.
From the beginning Trump said the nuclear agreement was a ‘bad deal’ - he has threatened to unilaterally pull out of the accord if it is not renegotiated.
Iran says that is out of the question.
“The difficulty for Mr Le Drian is that on all of these points we already know the position of the Iranians,” says Francois Nicoullaud, a Former French Ambassador to Iran.
“It’s almost as if he’s in the position of the beginning of a negotiation. On the ballistic programme for instance the Iranians consider it’s a question of sovereignty. They have no intentions to limit the programme just to please the Europeans or the Americans.”
Paris is clearly trying to position itself as the peacemaker between the US, the signatories of the deal, the so called P5+1 and the Iranians.
Le Drian is leading the European effort by focusing on complaints that aren’t within the accord - the ballistic missile program and Iran’s expanding involvement in regional conflict.
Trump, along with Israel, says that Tehran's development ever more powerful ballistic weapons threatens regional stability.
Investment still slow
Commentators say Iran is disappointed that the investment they were promised after they signed the deal failed to materialise - and banks are still wary that if Trump pulls out, he could unilaterally reintroduce sanctions.
Tehran is already battling with a stagnating economy and growing discontent.
“The Iranians are too disappointed in relations to the outcome of the nuclear agreement,” says Ardavan Amir-Aslami, a Paris based lawyer who deals with Iranian affairs.
“They won’t accept any further sacrifices until they have actual proof that something is in it for them.”
Le Drian is not without cards to play. Firstly he can reassure Tehran that trade between the two nations will continue to grow.
The oil company, Total, is a big trader with Iran. As is the carmaker PSA Peugeot-Citroën, which Peugeots under license in Iran.
“What Le Drian can do is protect trade,” says Clement Therme, a research fellow with at the International Institute for Strategic Studies in London.
“Trade is different from investment. He can also work with Chinese and Russian companies to ensure trade continues.”
Le Drian also brings cultural ties to the table. On Monday he opened an exhibition of pieces from the Louvre Museum in Paris.
A gesture that is highly appreciated in Tehran.
It will not go unnoticed either that Le Drian Europe’s first foreign minister to travel to Tehran since since the nuclear accords were signed in 2015.
“You have to remember that he is there in principle to prepare a State visit by Emmanuel Macron later this year,” says Francois Nicoullaud.
“This would be a big gift for Iranians. No major western head of state or government has visited Tehran since the Islamic Revolution in 1979. And the Iranians are well aware of this.”
The French can't promise that investors will flock back.
But with some delicate diplomacy they hope to convince both Washington and Tehran what many other western nations already firmly believe.
That keeping dialogue open and the nuclear deal in place is far better for the region than the alternative.