Opening the International Support Group for Lebanon meeting, Macron said it was "essential that all of the parties in Lebanon and regional actors respect the cardinal principle of non-interference" in the affairs of other countries.
Lebanese Prime Minister Saad Hariri and US Secretary of State Rex Tillerson attended the talks in Paris with representatives of the four other permanent members of the UN Security Council, along with Germany, Italy and Egypt.
The meeting took place against a backdrop of rising tensions in the Middle East linked to US President Donald Trump's decision to move the American embassy to Jerusalem, an announcement that was condemned again by Macron and Hariri.
"It complicates the peace process even more (between Israel and the Palestinians) and creates a new challenge to regional security," Hariri said in opening remarks at the meeting.
Macron added: "None of the region's problems will be resolved by unilateral decisions or the strongest imposing their will."
It's the first major gathering of key nations to discuss Lebanon's future since a crisis erupted following Hariri's shock resignation last month while in Saudi Arabia.
Hariri rescinded his resignation on Tuesday, drawing a line under a month-long crisis triggered when he announced from Riyadh that he was stepping down and remained outside Lebanon for weeks. His coalition government, which includes the Iran-backed Hezbollah group, reaffirmed a state policy of staying out of conflicts in Arab states.
Saudi Arabia was suspected of pressuring Hariri, a longtime ally, to resign on 4 November as part of its attempts to counter growing Iranian influence in the region.
In an unusual televised resignation statement made from Riyadh, Hariri lambasted Tehran and its Lebanese ally, the powerful armed movement Hezbollah, for destabilising his country.
A Lebanese source close to Hariri has reported that the leader travelled to Riyadh believing he was going to discuss economic projects but instead "found himself faced with a list of economic sanctions brandished by the Saudis against Lebanon."
Saudi Arabia and other Arab states accuse Iran of using armed proxies such as Hezbollah to expand its influence the region, from Lebanon to Yemen to Syria and Iraq.
Hariri remained in Riyadh for two weeks after his resignation speech, fuelling speculation that he was being held hostage.
Macron then intervened, inviting him to Paris for talks, after which Hariri returned home to a hero's welcome.
"Lebanon's stability is not only crucial for its inhabitants but for the entire region," Macron said Friday, demanding that the sovereignty of the small multifaith country, long a proxy battleground between its bigger neighbours, be respected.
Hariri said the fragile stability enjoyed by his country, which neighbours Syria, "appeared like a small miracle" in a region plagued by conflict.
"The desire of all in Lebanon is to save our democracy," he said.
Power play backfire
Hasni Abidi of the Geneva-based CERMAM research centre, which specialises in Arab affairs, described the gathering as "a sort of consecration, a re-legitimisation for Mr Hariri."
"The international community is validating a return to normal for Hariri," he said.
Riyadh's power play paradoxically led divided Lebanese factions to come together in order to avoid a political breakdown.
After consultations with various parties, including Hezbollah, Hariri announced Tuesday that he was withdrawing his resignation.
His cabinet members issued a joint statement to reaffirm their commitment to "dissociation" from regional conflicts, apparently putting an end to the month-long Hariri saga.
After Friday's talks Hariri will give a joint press briefing with French Foreign Minister Jean-Yves Le Drian and Amina Mohammed, the UN deputy secretary general.
The International Support Group for Lebanon was launched in September 2013 partly in response to the huge influx of refugees from the conflict in neighbouring Syria.