He did not say whether France is planning military action against Assad's government.
With increasing concerns about a U.S. -Russia proxy war in Syria, Macron insisted that "France will not allow an escalation or something that could damage the stability" of the region.
The French president does not need parliamentary permission to launch a military operation.
Syrian opposition activists and medics say a suspected gas attack last week in Douma killed more than 40 people.
The attacks came as negotiations were under way between Jaish al-Islam and the Syrian government over the last rebel-held bastion near the capital.
A joint military operation, possibly with France rather than the U.S.in the lead, could send a message of global unity about enforcing the prohibitions on chemical weapons.
But she says, "No final decision has been made".
The Kremlin spokesman is warning the USA and its allies against any steps that could destabilize the situation in Syria.
Asked to comment on possible US strikes, President Vladimir Putin's spokesman said Thursday that "it's necessary to avoid any steps that may fuel tensions in Syria". He added that it would have an "utterly destructive impact on the Syrian settlement".
Tensions increased further yesterday after US President Donald Trump warned Russian Federation to "get ready" for a missile strike in the war-torn country.
The U.S. and its allies have threatened to respond militarily to an alleged chemical attack near Damascus last weekend.
The country's president has Vladimir Putin has called for a calming of tensions.
Trump said on Twitter on Thursday that a possible military strike against Syria "could be very soon or not so soon at all".
Peter Cardillo, chief market economist at Spartan Capital Securities in NY said the escalation of the situation in Syria "is impacting.it could escalate to greater military conflict".
Erdogan says Turkey's warming ties with Russian Federation and Iran are "not an alternative" to its traditional ties to the West, adding that Ankara would "fight until the end" against Russia's support for Syrian President Bashar Assad and against USA support to a Syrian Kurdish militia that Ankara has labelled a terrorist group.
Referring to the allegation of a Russian military official that there was an attack, but it was staged by the White Helmets brigade component of the rebels in Syria, she said the intelligence provided "certainly paints" a different picture, and the President holds Syria and Russia responsible for the chemical weapons attack.
He said the United States is still assessing intelligence relating to Syrian President Bashar al Assad's involvement in the attack.
Assad spoke during a meeting with Ali Akbar Velayati, an aide to Iran's supreme leader.
In addition, a French frigate is stationed off of Lebanon in worldwide waters.
The council has already failed to agree on a response to the attack in three votes and has been deadlocked throughout the Syrian civil war.
British Prime Minister Theresa May has summoned her Cabinet back from vacation to discuss military action against Syria over an alleged chemical weapons attack.
The U.S., France and Britain have been consulting about launching a military strike. Most nations have foresworn use of chemical weapons, at least on innocent civilians.
Mattis' remarks at a House Armed Services Committee hearing followed a series of Trump tweets this week that initially indicated he was committed to bombing Syria but later suggested he was awaiting further advice and assessment.
A French frigate, UK Royal Navy submarines laden with cruise missiles and the USS Donald Cook, an American destroyer equipped with Tomahawk land attack missiles have all moved into range of Syria's sun-bleached coast.
It appears the British Parliament will not be consulted ahead of the United Kingdom action - which could potentially start within hours of Cabinet approval.
Formally, the prime minister has the right to go to war without approval from parliament, but a convention has been established in previous conflicts where MPs have a vote either before or shortly after military action begins.
Cabinet ministers have agreed on a "need to take action" against Syria, following a suspected chemical weapon attack that claimed the lives of dozens of people in the Damascus suburb of Douma.
Foreign Minister Jean-Yves Le Drian said Thursday that President Emmanuel Macron would decide whether to launch an attack over the "non-respect of the global convention against chemical weapons", which is a "red line" for France.
Meanwhile, US defence secretary James Mattis has said the country's military stands ready to provide President Trump with options for striking Syria. The sites reportedly include "two Syrian airfields, a research center and a chemical weapons facility".
"Now we have to make some further decisions, so they will be made fairly soon", added first-term commander-in-chief, who earlier appeared to equivocate on the timing of strikes.
The Syrian government has invited inspectors from the Organisation for the Prohibition of Chemical Weapons (OPCW) in the wake of the attack, but it is not clear whether they will be given access to Douma.