France, Lebanon and the Hariri family have close ties

At the invitation of the Paris government, Hariri is expected to travel from the Saudi capital to France in the next few days in a move that -- diplomats hope -- will ease regional tensions.

AFP explains France's role:

- Why is France involved?

Part of the reason is historical.

Links between France and multi-faith Lebanon go back at least to the 16th century when King Francis I signed an agreement with the Ottoman Empire giving the French royals the status of protectors of Christians in the Middle East.

With the fall of the Ottomans in 1920, Lebanon emerged as a contemporary state but it was administered by France under a League of Nations mandate until 1943 when it gained independence.

Since then, France has always maintained close ties with the unstable country which must, under its constitution, have a Christian as president and a Sunni Muslim as a prime minister. Lebanon has a large Shiite Muslim community too.

"What gives us (France) our power -- including in comparison with the United States -- is that we talk to everybody," said Denis Bauchard, Middle East expert at the French Institute of International Relations (IFRI).

"France has a special relationship in Lebanon with the three (religious) communities, including contact with the Shiites," he said.

Hariri resigned on November 4 in Saudi Arabia, blaming threats to his life and the "grip" of the powerful Iran-backed Shiite movement Hezbollah on the country.

His failure to return home afterwards led to speculation he was being detained by Saudi Arabia, which is locked in an increasingly tense battle for influence with Iran in the Middle East.

Is it just history?

No. French President Emmanuel Macron, a 39-year-old former investment banker, is also keen to make a mark in international relations after his victory in elections in May this year.

He held face-to-face talks with Crown Prince Mohammed bin Salman in Riyadh last week and dispatched his Foreign Minister Jean-Yves Le Drian to Saudi Arabia on Wednesday.

Macron is trying to fill a void of Western power in the Middle East: the United States has retreated under Donald Trump, while Britain remains wrapped up in its Brexit negotiations.

This has led to a whirlwind of diplomacy from Macron with varying degrees of success, from his efforts to find a solution in war-wracked Libya to a campaign in favour of maintaining the Iran nuclear deal.

- Is a resolution in sight?

Hariri's departure from Riyadh should help lower tensions after accusations from Lebanon's President Michel Aoun that his resigned prime minister was a "hostage" -- which has been denied by both Hariri and Saudi authorities.

"We hope that the crisis is over and Hariri's acceptance of the invitation to go to France is the start of a solution," Aoun said on the official presidential Twitter account on Thursday.

The French-language Lebanese daily L'Orient-Le Jour said France had "achieved the unexpected by inviting Hariri" to leave Riyadh, where his family is also staying.

"The exit proposed by the French president... has lowered tensions a notch," the daily said on Thursday.

- Will Hariri stay in Paris?

Macron was quick to dismiss speculation that Hariri was going into "exile" in France, but there has also been no confirmation that Paris will simply be a way station en route back to Lebanon.

Hariri's family have properties and long-standing links in France that go back to the beginning of the 1980s when the then-mayor of Paris, Jacques Chirac, become close to Saad's father, a wealthy real estate developer who had made his fortune in Saudi Arabia.

Rafik Hariri made a series of investments in France and headquartered his group Oger International in a Parisian suburb.

His friendship with Chirac would turn overtly political after 1992 when Hariri became prime minister of Lebanon. The Frenchman was elected president three years later.

Chirac was the only head of state to attend Hariri's funeral in Beirut in 2005 after he was killed in a bombing.

After he left office and retired in 2007, the French leader lived for around eight years in a luxurious Paris apartment overlooking the river Seine which is owned by the Hariri family.