French Prime Minister Manuel Valls said on Tuesday any compromise or arrangement with Syrian President Bashar al-Assad to reach a political solution was impossible as far as his country was concerned.

"We will do nothing to strengthen the regime," Valls said in a speech to parliament to explain France's decision to launch reconnaissance flights over Syria.

"The urgency, on the contrary, is to reach an agreement that definitively turns the pages of the crimes of Assad ... With a man responsible for so many dead and crimes against humanity, no compromise or deal is possible."

Valls again ruled out sending French ground troops to Syria, but said that if a regional coalition was created to intervene against Islamic State militants then Paris would support it.