"Adding war to war has never furthered the cause of peace," Bruno Retailleau, the leader of the mainstream right Republicans in the Senate, said in a tweet on Saturday. "This one-off show of force risk encouraging terrorism. It gives comfort to the idea that the West is hostile to the Arab world."
Like other critics, Retailleau criticised Macron for hitching France's foreign policy to that of US President Donald Trump.
"It's a mistake and the lessons of the past and our failures in the Middle East seem to have already been forgotten."
The air strikes "take us down a road with unpredictable consequences that are potentially tragic", National Front leader Marine Le Pen tweeted. "France has again missed the opportunity to appear on the world stage as an independent power in favour of parity in the world."
French diplomatic independence
The attacks are "an irresponsible escalation" for the sake of American revenge, Jean-Luc Mélenchon, of the hard-left France Unbowed, declared.
He, too, was worried about a supposed blow to France's position as a diplomatic player.
"We are not at all in an independent situation which wold allow us to have a possible role of mediation," he told French television.
Mélenchon also cast doubt on the alleged proof that President Bashar al-Assad has used chemical weapons, the justification for the attacks.
"The proof of who used these weapons is not given anywhere," he claimed. "How can we understand that, at the very moment when there is an investigation, they bomb even before the results of the inquiry in question?"
Socialists back Macron
The government defended French participation in the attacks and Macron's supporters praised them.
And they were not alone.
"A just response by France and her allies to the Syrian regime's use of chemical weapons. Let us salute the commitment and professionalism of our armed forces," tweeted Xavier Bertrand, the president of the Hauts-de-France region, who quit the Republicans earlier this year.
"The Damascus regime's repeated chemical attacks on its people made a reaction necessary," Socialist Party leader Olivier Faure said on Facebook, adding a call for new discussions at the UN. "There is no long solution unless the conditions for a negociated transition are laid out."
France "has measured up to the singular and historic role that is her own" in acting "alongside of the American and British democrats", Jean-Christophe Lagarde of the liberal UDI, which supports the government declared in a statement.
Syrian President Bashar al-Assad has "crossed a red line" in using chemical weapons, Christophe Castaner of Macron's Republic on the Move said in a tweet. "France could not remain blind and mute when faced with this barbarity. Last night's strikes in Syria are necessary and salutary for the Syrian people."