Hariri "will come to France and the prince has been informed", French Foreign Affairs Minister Jean-Yves Le Drian told reporters, referring to Saudi Crown Prince Mohammed Bin Salman with whom he held talks late on Wednesday.
Le Drian was due to meet Hariri in his villa in Riyadh on Thursday afternoon after meeting King Salman and Saudi Foreign Affairs Minister Adel al-Jubeir.
French President Emmanuel Macron's office said on Wednesday that Haririand his family had been invited to France for a "few days" with Mohammed Bin Salman's agreement but that did not mean he would stay there in exile.
Macron has stressed that Hariri should be able to return to Lebanon to confirm or withdraw his resignation in person.
Hariri tweets he's fine
Following Lebanese President Michel Aoun's declaration on Wednesday that he considered his prime minister to be detained against his will, Hariri said on Twitter that he was in good form.
"I want to repeat and confirm: I am totally, totally fine and I'll come back, God willing, to beloved Lebanon like I promised you all. You'll see," he tweeted.
Aoun, who has yet to accept Hariri's resignation, was elected with the support of the Iranian-backed Shia-Muslim militia Hezbollah, which Hariri criticised in his resignation announcement.
French employees owed arrears
Hariri, who was born and raised in Saudi Arabia and has Saudi nationality, represents a rival Sunni-Muslim-based faction and has Saudi backing.
He also has investments in the kingdom, including a majority holding in troubled construction company Saudi Oger.
In September he promised Macron to pay arrears owing to French employees of the country, their lawyers have said.