President Francois Hollande said on Monday that French air strikes against Islamic State militants in Syria would be necessary.
"We are part of the coalition in Iraq (against Islamic State)," Hollande said in a news conference with Nigerian President Muhammadu Buhari.
"We started reconnaissance flights (in Syria) to enable us to consider air strikes if they were necessary and they will be necessary in Syria."
France until now had only taken part in air strikes against Islamic State in Iraq because it feared such action against the group in Syria could strengthen Syrian President Bashar al-Assad.
Paris has also been heavily engaged in the fight against al-Qaeda militants in West Africa and has been providing logistical support and intelligence to Nigeria and neighboring states combating Boko Haram militants.
"Boko Haram is linked to Daesh. It receives aid and support from this group. The fight against Boko Haram is the fight against Daesh," Hollande said, referring to the Arabic acronym for Islamic State.
"It is no longer possible to distinguish terrorism from regions. It's the same terrorism inspired by the same death ideology," he said.
Hollande last week said Paris was beginning flights over Syria because of the expansion of Islamic State over the last year and the threat its militants could have on French interests at home and abroad.
Paris was ready to join air strikes on Assad's forces in Syria in 2013 before U.S. President Barack Obama backed off the plan.
