A total of 412 lawmakers backed the bill, which will notably scrap cash handouts for lawmakers to spend on areas and NGOs of their choice.
Parliament had last week already voted through aspects of the law banning MPs and ministers from employing their family members, as Macron's new centrist government seeks to restore public trust in politicians.
“Practices… that were probably tolerated, maybe accepted for some time, are no longer accepted today,” Prime Minister Edouard Philippe told French radio.
The presidential campaign that saw Macron take power in May, becoming France's youngest-ever president, was rocked by allegations that his rightwing rival Francois Fillon employed his wife as a publicly-funded assistant for years despite little evidence of any work.
Fillon was the odds-on favourite in the race until revelations at the end of January that he had employed his Welsh-born wife Penelope.
Macron has reconsidered plans to give his wife an official status. AFP
But his poll standings plunged as he struggled to convince voters that his wife and their children had worked to justify their pre-tax income of around 900,000 euros ($1 million) over 15 years.
The Republicans party nominee was charged with misusing public money in March, just weeks before crashing out of the first round of the presidential election. He denies any wrongdoing.
Plummeting approval rating
The passage of the ethics bill will be a welcome achievement for 39-year-old Macron, who has seen his approval ratings plummet after less than three months in office.
One survey published last week showed just 36 percent of respondents held a positive view of the former economy minister and investment banker, who shot to power promising to overcome France's entrenched right-left divide.
He has since come under fire for his labour reform programme, budget and public spending cuts as well as a plan to create an official First Lady position for his 64-year-old wife Brigitte.
Proposed defence cuts — part of a plan to trim 4.5 billion euros ($5.3 billion) to bring France's budget deficit within EU limits — led to a public spat last month with the head of the French armed forces, General Pierre de Villiers.
Macron rebuked the general after he had complained about the impact of cuts at a time the army was in action in the Middle East and West Africa as well as at home. De Villiers resigned a few days later.
The young president faces more turbulence in September, with some union leaders calling for demonstrations against labour reforms at the centre of Macron's election manifesto.
Parliament last week adopted a bill allowing the government to fast-track changes to the labour code to give employers more power to negotiate working conditions directly with workers.
The hardline CGT union has called for countrywide strikes and protests on September 12.
U-turn over First Lady
Macron has reconsidered plans to give his wife an official status, which he had promised on the campaign trail, backing down in the face of attacks from the left and a petition against the move.
Critics saw a double standard in Macron pursuing the plan while pushing through legislation to stop deputies hiring their own relatives.
A “fake jobs” scandal struck close to home in June, when Macron's justice minister, Francois Bayrou, stepped aside to fight allegations that his small MoDem party misused European Parliament funds.
Bayrou had been tasked with crafting the ethics law — measures he himself advocated.
Two other MoDem cabinet members — then defence minister Sylvie Goulard and European affairs minister Marielle de Sarnez — also quit over the accusations that MoDem had misused the European Parliament funds to pay assistants actually based in France.
The same practice has embroiled several other MEPs, the most high-profile case involving far-right leader Marine Le Pen, Macron's rival for the presidency.
Under the new law, hiring a spouse, partner, parents or children will be punishable by three years in prison and a fine of 45,000 euros ($53,000), with in some cases an order to refund the sums paid out.