Macron will also have to allay fears that the overwhelming majority that his centrist Republic on the Move (REM) party is set to enjoy in parliament will shut out healthy democratic debate.
Here are three challenges for Macron, his government and his MPs.
How strong is Macron's mandate?
"It's a muted, incomplete victory because he does not enjoy the backing of a majority of the French people," pollster Gael Sliman told AFP.
The low turnout could be explained partly by election fatigue, but also by "those who may not agree with Macron but do not want to block his path," said Sliman, of the Odoxa polling institute.
Political scientist Jerome Sainte-Marie noted that only one in three potential voters actually cast ballots for REM candidates, given the 49 percent turnout in Sunday's first-round parliamentary vote, in addition to eligible voters who did not register and those who cast blank or spoilt ballots.
"The abstention reflects the disaffection (with politics) of part of the French electorate, notably the working class," Sainte-Marie said, adding: "Young people... were especially demoralised by the presidential election."
The record-low turnout -- the lowest in six decades -- "reveals a pretty weak sociological and political foundation for the new administration," said Sainte-Marie, of the PollingVox institute.
The Macron team itself recognised the liability, with spokesman Christophe Castaner calling the low turnout "a failure of this election" and emphasising the need to reach out to those who stayed away.
What will the opposition look like?
"What is new about this election is that opposition forces have crumbled," said Martial Foucault, director of the Cevipof research centre.
"We don't know who will really embody the opposition, and that is the gamble Emmanuel Macron took and won -- spreading his political tent as widely as possible to the left and right," Foucault told French radio.
Sainte-Marie added that he thought the opposition was "both politically and socially demoralised", but that street protests were unlikely to gain traction.
"You can't stop reforms by taking to the streets, but through strikes, as happened in 1995," Sainte-Marie said, referring to a month-long work stoppage that forced then-president Jacques Chirac to scrap a pension reform plan.
"Today I don't see who can strike" without risking their jobs or taking a financial hit, he said. "Demonstrations in reality don't bother governments very much." Footage of violence by a handful of protesters can "discredit a march by 500,000 people."
Philippe Braud of Sciences Po university agreed, saying: "The reforms are obviously unpopular but necessary, and they will pass" in the new political landscape created by the sea change in parliament.
Sainte-Marie noted that even though Macron won only one-fourth of the votes in the first round of the presidential election, "today there is no credible opposition" to the 39-year-old former investment banker.
The Macron juggernaut left behind an opposition made up of "irreconcilable parts" -- the radical left, the far right and the traditional left and right, Sainte-Marie said.
What to expect from a parliament of newbies?
Foucault warned that with scores of REM lawmakers taking elective office for the first time, "there will be a learning curve, a period of discovery that may lead to a kind of disillusionment."
Furthermore, "these new lawmakers will want to do well, to succeed on a political programme that in my view is not yet totally clear. We don't know really what targets they have. We have some economic details but it's very vague regarding social benefits," Foucault told French radio.
What is more, Sliman said, the new MPs owe their political life to Macron, who launched his movement barely a year ago. "Never have there been so many lawmakers so beholden to their leader," he said. "They owe absolutely everything to him."
Macron runs the risk of believing "that just because everyone around him agrees with him, all the French do," Sliman said. "He'd be wrong."
Eyewitness? Submit your stories now via social or:
Email: news@pulselive.co.ke
