In "tourist zones", like the iconic Champs Elysees in Paris, shops could open every Sunday and until midnight every day. Photo: Oh Paris/Flickr
The reforms, presented by France's youthful Economy Minister Emmanuel Macron, aim to shake up Europe's second-biggest economy as it battles with stubbornly high unemployment and near-zero growth.
One of the most controversial planks of the plan extends the number of Sundays that shops can open annually from five to a maximum of 12.
In areas designated "tourist zones" — such as the iconic Champs Elysees in Paris — the proposed law would allow shops to open every Sunday and until midnight every day, bringing the French capital more in line with London.
But this has proved hugely divisive in a country where the maximum working week is fixed at 35 hours and leisure time is sacrosanct.
After enormous demonstrations against the reform package last year, several unions plan to hit the streets again on Tuesday to protest against what they see as the "acceptance of work on Sundays and at night."
Another facet of the law — opening up previously heavily regulated professions such as notarial lawyers — sparked the unusual sight of these white-collar workers marching through the streets.
Other measures aiming to prise open up the notoriously closed French economy include throwing open inter-city bus routes to competition and privatising the airports of Nice and Lyon.
Under pressure from Brussels, the reform package also aims to improve the parlous state of France's public finances.
Paris sent shockwaves through the European Union last year by going back on a promise to get its budget deficit under EU limits by this year, pushing the deadline to 2017.
'Fox in chicken coop'
Deputies open a two-week debate on Monday on the reforms that have not only split the parliament down party lines but also opened up divisions within party groups.
A left-wing rump of the ruling Socialist Party is bitterly opposed to the Sunday trading law and has warned that it is "not votable in its current form."
Meanwhile, some in the right-wing UMP party, which has been called to vote against the package, will defy party whips.
The Greens have attacked what they criticise as "deregulation and austerity" and the far-left party has described the package as "a fox in a chicken coop."
In a sign of how divisive the package is, some 3,000 amendments to the law have already been introduced, with more expected.
The reforms are likely to be "finessed" during the debate, Macron has acknowledged.
However, a poll released on the eve of the debate suggested that French voters are broadly in favour of the measures.
Around three in five voters (61 percent) said they would vote in favour of the package, compared to 38 percent opposed, according to the survey by FTI Consulting.
Guillaume Granier, from FTI Consulting, said the recent attacks in Paris, where Islamist gunmen killed 17 people over three days, may have made voters less tolerant of political bickering.
"Maybe we are starting to see the beginning of a change in public opinion … the massive and unprecedented demonstration of national unity that followed the January attacks definitely marked a shift," said Granier.
Around seven out of ten voters are in favour of extending Sunday trading and nearly eight out of 10 agree with opening up the so-called "regulated professions."