A source close to Hariri said on Thursday that the former Lebanese prime minister is expected to leave Saudi Arabia for France within 48 hours.
In a quick reaction to Aoun's comments, Hariri tweeted that he was fine and will return to Lebanon as promised.
"He will come to France and the prince has been informed", Le Drian told reporters, referring to powerful Saudi Crown Prince Mohammed Bin Salman with whom he held talks the night before.
The fundamental Saudi Arabian gamble in Lebanon is to try and dismantle the existing government, force fresh elections and get rid of the Shia-Hezbollah elements in the Lebanese government.
He said that the main aim now is that Hariri can return to Lebanon without any conditions or restrictions on his freedom and, once back in Lebanon, that he can decide whether to step down as the prime minister, the news agency reported.
Hariri's abrupt resignation while he was in Saudi Arabia and his continued stay there have caused a political crisis in Lebanon and thrust it into the bitter rivalry between Riyadh and Iran.
In his resignation speech televised from Saudi Arabia, Hariri denounced Iran and Hezbollah for sowing friction in Arab states and said he feared assassination.
It was the first time Michel Aoun described Hariri as a detainee of the kingdom since the resignation 12 days ago, which was delivered from Riyadh. Hariri's family has longtime connections to France.
Lebanon, long abused by regional powers seeking to exert influence, was plunged into uncertainty this month after Hariri's shock resignation, announced on television from Riyadh.
Its concerns have increased since Iran-aligned Houthi rebels seized the capital of neighbouring Yemen in 2014 and since the 2015 deal over Iran's nuclear programme, which led to the lifting of international sanctions.
In his resignation statement, Hariri accused Iran and its ally Hezbollah of taking over his country and destabilising the broader region.
Aoun, a Christian, is a political ally of Hezbollah, the heavily armed Muslim movement that is backed by Iran.
"Hezbollah has kidnapped the Lebanese system", he added.
France, Lebanon's onetime colonial ruler, has been trying to mediate the crisis.
Whenever American officials came to visit the region, the flames of war and tension went up in some area there, he concluded.
He asked Lebanese media to join in a campaign to reinforce national unity. Who knows? One day we may start even believing the click bait masterpieces of the New York Times.
Earlier both Hezbollah and Iran accused Saudi Arabia of pressing Israel to launch attacks in Lebanon. Speculation has been rife that the meeting was the reason for Riyadh's surprise summoning.
On Thursday, Saudi Foreign Minister Adel al-Jubeir said Saudi Arabia was consulting with its allies about what leverage to use against Hezbollah.