The Republicans fared better than the Socialists, hanging on to 131 seats, down from over 200 in the last parliament, and remain the main opposition party.
The huge majority shows the success of Macron's new party, which did not exist just 16 months ago.
French President Emmanuel Macron is poised to rearrange his Cabinet after his new centrist party engineered a landslide in the country's parliamentary election, enabling the government to quickly start passing its first big laws.
And the youngest member of Macron's government, is 33-year-old Mounir Mahjoubi, who beat off Socialist Party leader Jean-Christophe Cambadelis and a hard-left candidate for a seat in the multi-ethnic 19th district of Paris.
Turnout will be closely watched after it hit a near 60- year low in the June 11 first round of voting, leading some to warn Macron that his mandate is not as strong as he thinks. One of the tasks ahead is to "avoid a mess" in the La Republique en Marche, which is an assembly of people with different political views who are disillusioned with traditional parties on the left and right, as well as of people with no political experience at all.
The president's party came out on top in the second round of the general election on Sunday, receiving 308 seats in the parliament. "It's about loyalty", he said.
The old parties collapsed in the presidential election that brought Macron to power a month ago.
Security at mosques to be reviewed after Finsbury Park attack, says PM
She said the driver of the van acted alone, and police declared it a terrorist incident within eight minutes. One person has been arrested. "Inquiries continue.
"After the reforms, which we expect Macron to implement, France could turn into the strongest of all major economies in Europe in the next decade, outclassing a Germany that is resting on its laurels and a United Kingdom that (through Brexit) is impairing its long-term growth prospects", said Holger Schmieding, chief economist at German bank Berenberg.
TRT World speaks to Alexandre Kouchner, a political commentator, about the election results.
Mr Macron wants to use his majority in parliament to pursue his agenda of changing labour laws and overhauling France's social security system.
But he will need to be mindful of a budget deficit that the Bank of France forecasts will once again breach the European Union cap of three per cent of national income this year. "Long live the Republic, long live France!".
Of the 577 elected lawmakers, 308 were from the centrist LREM movement, making it France's new ruling party for the next five years.
There will be a record 224 women in the new intake of lawmakers, smashing the former high mark of 155 elected in 2012.
The new parliament will be almost six years younger on average, have a record 224 women lawmakers, and will be strikingly more varied in background - if politically less experienced. Despite 2016 polls predicting she would win between 30 and 40 seats, the nationalist party only secured eight seats in parliament.
Moreover, France's political mood remains volatile and one indicator of remaining voter unease is the exceptionally low turnout in the legislative elections, estimated at 43%.