Fabius said a statement by President Francois Hollande Friday that Russian airstrikes must target "Daesh and only Daesh (the Arabic acronym for ISIL)", did not exclude other groups like the Al-Nusra Front.
"Of course, it is a concise formulation, it is Daesh and groups considered as terrorists," Fabius told Europe 1 radio in an interview, referring to Hollande's statement, AFP reported.
Moscow has launched more than 70 airstrikes in Syria since last Wednesday, following a formal request by President Bashar al-Assad. Moscow does not deny that ISIL is not its military's only target, as other terrorist groups will also be pursued.
"If it looks like a terrorist, if it walks like a terrorist, if it acts like a terrorist, if it fights like a terrorist, it's a terrorist," Russian Foreign Minister Sergei Lavrov told reporters at the UN General Assembly in New York last week.
President Barack Obama has nonetheless called Russia's dramatic strikes a "recipe for disaster," while British Prime Minister David Cameron urged Russian President Vladimir Putin Sunday to "change direction" in Syria and recognize that Assad must be replaced.
Fabius warned of the risk that the Syrian conflict could turn into a wider religious war.
"When you see a conflict which at first was a civil war, becoming a regional war involving international powers, Russia, Iran, the US, the risks are serious," he said.
"The most terrifying risk is that the conflict becomes religious: If you have Shiite (Muslim) populations on one side with their allies, and Sunni populations on the other side with their allies, it is an inferno which can be extremely dangerous."
France, which has been targeting ISIL in Iraq for the past year, began striking the group in Syria eight days ago.