Friday's meeting will be attended by US Secretary of State Rex Tillerson and representatives of the four other permanent members of the UN Security Council -- the United States, France, Britain, Russia and China -- along with Germany, Italy and Egypt.
"The aim is to support the political process [in Lebanon] at a crucial moment," the French foreign ministry said, minutes after Hariri announced he had rescinded his resignation.
"It will send a message both to the various parties in Lebanon and to countries in the region."
French officials say they hope to encourage foreign investment by supporting Hariri's economic programme and strengthening the army.
Hariri's surprise resignation, announced on television from Saudi Arabia, led to accusations that he had been effectively kidnapped by the Saudis.
In his statement he accused the Shia-Muslim militia Hezbollah, which is backed by Iran, of destabilising Lebanon.
Saudi Arabia, backed by the US, is locked in battle with Iran for influence in the Middle East.
French President Emmanuel Macron helped head off the crisis by inviting Hariri to Paris, where he stayed for five days before returning to Lebanon.