PARIS - With U.S. President Donald Trump tightly aligned with Saudi Arabia against Iran, France is positioning itself as a broker between the Sunni and Shi'ite Muslim rivals, but neutrality may leave it with little leverage.

With tensions between Riyadh and Tehran rising sharply since Saad Hariri's resignation as Lebanon's prime minister, President Emmanuel Macron made an unscheduled stopover to meet Saudi's powerful Crown Prince Mohammed bin Salman on Thursday.

The move, made ahead of a possible visit by Macron to Iran next year, is in line with the young president's foreign policy style of being engaged but non-committal, trying to mediate between all sides without unsettling anyone.

"There is a stronger capacity for initiative than before," former foreign minister Alain Juppe told journalists on Friday. "It reminds me a little of (President Nicolas) Sarkozy leaving for Georgia in 2012. It's good that the president is getting his hands dirty. It's an initiative he has taken and may work."

During a visit to Dubai on Thursday, Macron was carefully balanced, calling for a firm international stance over Iran's nuclear and ballistic missile programme while implicitly warning that Riyadh's approach towards its rival was excessive.

That tightrope walking may help protect French business ties in Iran and buy time with the Saudis, but diplomats are concerned the 39-year-old president, new to international affairs, may ultimately leave France exposed.

"We should be reducing our exposure to the region. We have a lot of hits to take without having pressure points to weigh on them," said a French diplomatic source. "I don't think it's in our interest to play a role in quarrels between powers."

Under Sarkozy and Francois Hollande, who respectively aligned themselves with Qatar and Saudi Arabia, France nurtured new links with the Sunni-ruled Gulf Arab states and adopted a tough stance on Iran during nuclear negotiations.

But during his election campaign, Macron promised a different approach. He openly criticised Saudi Arabia and Qatar for their perceived support of Islamist groups across the region, and since the nuclear deal brought an end to sanctions, France has revived old business and investment ties to Iran.

Yet over the same period, Saudi's 32-year-old crown prince has shaken up the landscape. He has forged close ties with Trump, adopted an ever more confrontational line against Iran and, in the past week, dramatically uprooted his own nation's political structures.



BALANCING ACT

"France is trying to act as a balance between Iran and Saudi Arabia," said Dominique Mosi, special adviser in charge of international relations at the Paris-based Montaigne Institute.

"At a time when the situation is worsening in the region, it is offering itself as an intermediary after Trump chose one camp over the other," he said, referring to Trump's decision to decertify the Iran nuclear deal.

Macron has tried to be nuanced, offering something to everyone. He has vowed to stick to the nuclear deal with Iran, while talking up ties with Trump and Saudi Arabia. At the same time, he has threatened new sanctions against Tehran over its ballistic missile programme and promised to address its growing hegemony in the region. Iran for one isn't buying it.

"I don't think this policy works," said a senior Iranian official speaking on condition of anonymity. "If a country like France tries to appease, the effect on someone like Trump will be contrary and will simply embolden the administration."

French officials insist Paris has a role to play in various international conflicts given its position as a veto-wielding member of the U.N. Security Council and its historical ties in the Middle East. They say that by remaining neutral, France will prove credible and consistent in the long-term.

Since Macron took power he has offered to mediate in Libya, Ukraine, Syria, the Qatar crisis and even Venezuela, each time carefully trying to avoid taking sides. But it may not pay off.

"France has understood full well that there is a leadership problem on the part of the Americans and it understands that it's potentially an opportunity to make a difference," said Jalel Harchaoui, a geopolitics researcher at Paris 8 University.

"But so far it seems that Macron and his team have been very distracted, in a hurry to announce big initiatives but delivering very little."

(Additional reporting by Jean-Baptiste Vey, Sophie Louet, Yves Clarisse, Editing by William Maclean) ((john.irish@thomsonreuters.com; 0033-1 49 49 53 42;))