French voters have traditionally rallied behind their new leader in the legislative elections that follow the presidential ballot. With a majority in Parliament and hundreds of lawmakers who are new to politics, the president would hold extensive control over the government.
A second round of voting takes place next Sunday.
With 90 percent of votes accounted for, Macron's La Republique En Marche (REM) and allies had won 31.9 percent support, Interior Ministry results showed.
The far-right National Front (FN) was seen third with 13.1-14 per cent.
If, as polls project, Macron and his fledgling party win a commanding majority in next week's second round, it will be another blow for the mainstream parties on the right and left which failed to get a candidate into the presidential run-off. Prime Minister Philippe urged French voters to improve on Sunday's turnout, stressing the importance of going out to vote.
Jean-Luc Melenchon's far-left party had 11 percent, while the Socialists of former President Francois Hollande tumbled to 7 percent.
Half of people in the party have never been involved in politics.
"We have to restore trust", said Christophe Castaner, who is also minister for parliamentary relations, on Monday.
Collomb also expressed gratitude to the law enforcement service for ensuring the security during the election amid terror threat. His party looks on course to win 70pc of the seats in the National Assembly - an astonishing outcome, one of the many election results that would have been dismissed out of hand by political experts a few months before it happened. Marine Le Pen's leadership is now openly questioned, even by her deputy President Florian Philippot.
Macron had thrown Les Republicains off balance by nominating two high-profile party members, Edouard Philippe and Bruno Le Maire, as his prime minister and economy minister.
Responding to the criticism, a senior party official of Macron's Republic on the Move (LREM) party said there would be no riding roughshod over alternative views.
Macron was a political unknown three years ago and is heading a start-up party, but as the scale of his likely victory emerged on Sunday, his opponents saw a danger to democracy.
If LREM fails to win a majority, Mr Macron will have to strike deals to push through his manifesto commitments. According to the projections following the first round of the country's parliamentary election, Macron's En Marche! party is leading by a huge gap.
Meanwhile, German Chancellor Angela Merkel has congratulated Macron over the "great success" of his party after projections showed his win. The Socialists, who dominated the last Assembly are expected to suffer a stinging defeat and win just a few dozen seats.
Less than 50 percent of the 47.5 million electors cast ballots - showing that Macron has limited appeal to many voters.
Emmanuel Macron waves after voting in the first of two rounds of French parliamentary elections. Those talks will begin after next Sunday's second-round vote.
Macron's year-old centrist movement, Republic on the Move, is seeking an absolute majority to be able to implement his campaign promises, which include simplifying labour rules and making it easier to lay off workers in hopes of boosting hiring.