The announcement comes after a massive assault launched by Syrian government and allied forces on February 18 to retake the enclave, which has been out of regime control since 2012.
The strikes came a week after an alleged gas attack that killed more than 40 people outside Damascus, but which Syria said was a "fabrication" intended to justify military action.
The conflict has left more than 350,000 people dead, according to the Britain-based Syrian Observatory for Human Rights.
Macron issued a statement shortly after huge explosions were heard in Syria's capital early Saturday.
The world leaders announced that the strikes targeted positions linked to the chemical weapons facilities of the Syrian government.
Theresa May announced that Britain had joined France and the United States in launching strikes against Syria.
The strikes had been expected since harrowing footage surfaced of the aftermath of the alleged toxic gas attack in the Damascus suburb of Douma.
Donald Trump yet to make final decision on Syria; will speak to British, French leaders: White House
The White House press secretary said the Trump was to confer with Emmanuel Macron and Theresa May on the action to be taken against the Assad regime.
Trump is believed to be considering standoff missile strikes against facilities related to the production and delivery of chlorine and sarin or sarin-like agents.
Russian forces bombed US-backed fighters in Syria's eastern province of Deir Ezzor early Saturday, the US-led coalition said after Moscow denied the claim.
A human rights group said those killed in the Idlib province died from suffocation and the effects of the gas.