With 97% of the vote in, Macron's La Republique En Marche party had won 300 seats. Its political ally, the Mouvement Démocrate, MoDem, won 41 seats.
That margin of victory would give Macron, a pro-European centrist, the large majority he craves to further his political revolution -- and would inflict a further blow on the country's traditional ruling parties. The conservative Les Républicains and their allies trailed with about 129 seats.
The center-left Socialist Party and their allies were projected to win 41 to 49 seats. Party leaders began reacting to the projected results soon after polls closed closed Sunday evening.
The far-right National Front won 8 seats.
"This evening despite an alarmingly low turnout, the triumph of Emmanuel Macron is indisputable, the defeat of the left is unavoidable, the defeat of the Socialist party is without appeal, the right is facing a real failure," said Jean-Christophe Cambadélis, the leader of the Socialist party.
François Baroin, the leader of Les Republicains, also remarked on the low turnout.
But he told BFMTV that Macron was "the artisan of this victory" and wished him success.
Macron's party, founded just a year ago, won the first round of elections on June 11 with less than half of eligible voters going to the polls.
Turnout again looked set to be low for the second round. Nationwide, it stood at just over 35% as of 5 p.m. local time (11 a.m. ET) on Sunday, France's Interior Ministry said on its website, significantly down compared with the same time in the 2012 election.
Macron won the French presidency last month without the support of a traditional mainstream party, as his newly minted En Marche! movement helped carry him to a convincing election victory
over far-right candidate Marine Le Pen.
How the elections work
To win a seat outright in the first round of voting, candidates had to win more than half the votes, which must account for at least a quarter of the registered voters.
If no single candidate managed to achieve that target, then all candidates who won at least 12.5% of registered voters advanced to the second round. The winner from the second round will then advance to Parliament.
According to BFMTV, more than 1,000 candidates ran in Sunday's elections.
La Republique En Marche and the Mouvement Démocrate won a combined 32.3% of the vote in the election's first round. The established Les Républicains trailed with 15.8% of the vote.
Both the Republican and Socialist parties, which have traditionally governed during the time of the Fifth Republic, struggled with turnout.
Le Pen's right wing National Front party garnered 13.2% of the vote in last Sunday's first round and was originally expected to take one to four seats. Jean-Luc Mélenchon's far-left party
claimed 17 seats after accounting for 11% of the vote in the first round.
Mistrust in politics
Though Macron and his party received a majority, leaders from across the spectrum were quick to point out that the low turnout meant the victory might not amount to a full-throated mandate from the French electorate.
"The low level of participation shows that there is a high level of mistrust in politics," Macron's far-right opponent in the final round of the presidential election, Le Pen, said. "The extremely low turnout considerably weakens the legitimacy of the new national assembly and this quinquennium begins on a very bad basis."
Mélenchon, leader of the far-left insoumise movement, had a similar view. "We have good news. First of all, the extremely low turnout today has an offensive political significance. Our people have entered a form of general civic strike in this election."
Edouard Philippe, the center-right politician whom Macron selected as his prime minister, called the vote a "frank majority" and said, "through the vote, the French people chose hope over anger." Yet he added that "low turnout is never good news," noting that the government had an "obligation to succeed."
"Tonight, the time for action is starting for the new presidential majority," Philippe said.
The newly elected President is leading a country suffering from high unemployment, a stagnant economy and security worries. Macron is hoping to carry out the far-reaching reforms he promised during his campaign.