Macron’s tough-talking over chemical weapons comes after the deadly nerve gas sarin was used in an attack in Idlib, Syria, in April.

Up to 100 people were killed in the atrocity that shocked the world and prompted Donald Trump to fire a salvo of Tomahawk missiles at a Syrian airbase.

But during his meeting with Putin, Macron said that France would respond immediately to any more chemical weapons attacks by the Russian-backed Syrian regime ruled by tyrant Bashar al-Assad.

Speaking at a joint press conference outside the palace, Macron said: “A very clear red line exists on our side, the use of chemical weapons by whomever.”