In one corner is centrist Emmanuel Macron, with his pro-globalisation, pro-EU world view.
In the other, far-right candidate Marine Le Pen, who champions "nationalism" and a "France-first" approach.
"The country Mr Macron wants is no longer France, it's a space, a wasteland, a trading room where there are only consumers and producers," Le Pen told thousands of supporters in Nice on Thursday.
Macron has a starkly different message: "I will be... the voice of hope for our country and for Europe," he said after the April 23 first-round vote.
Le Pen and Macron, who says he is "neither of the left nor the right", eliminated France's traditional political forces to reach the May 7 run-off.
The 39-year-old former investment banker, who had never before stood for election, started his centrist movement only 12 months ago but is now on the cusp of becoming France's youngest-ever president.
Despite his lack of political experience, polls currently show he will beat Le Pen by around 20 percentage points.
President Francois Hollande launched Macron's political career, picking him as an economic advisor and then parachuting him into his Socialist government as economy minister.
Sensing a worldwide shift away from established parties, Macron turned his back on Hollande and quit the cabinet in August to concentrate on building up his own centrist political movement "En Marche" (On the Move).
Since then, he has amassed over 250,000 members and confounded critics who said his appeal would not reach beyond young, urban professionals.
In politics as well as his personal life, Macron has broken traditions.
The theatre and poetry lover from a middle-class family in Amiens, northeast France, fell for his secondary school drama teacher, Brigitte Trogneux.
A 64-year-old mother-of-three, a quarter of a century older than Macron, she left her husband and married the young prodigy in 2007.
The unshakeable confidence with which Macron pursued Brigitte has been evident throughout his career.
But it tripped him up after he finished top in the first round, when he gave what many saw as a triumphalist speech and then held a party at a Paris bistro.
Opponents and allies were quick to remind him that victory was not assured, and he threw himself into campaigning.
Watch: Macron campaigns in Northern France
Unlike Macron, 48-year-old Le Pen is steeped in hard-edged politics.
Her pugnacious father Jean-Marie Le Pen reached the run-off of the 2002 presidential election, but was soundly beaten by the centre-right Jacques Chirac.
Fifteen years later, his gravel-voiced daughter believes she can become France's first woman president, and the first from the National Front (FN) party that her father founded.
She faces an uphill task as her younger rival appears to attract a broader spectrum of voters.
She also goes into the run-off with several investigations hanging over the FN and her entourage for alleged funding scandals, while she is also being probed after tweeting pictures of Islamic State jihadists' atrocities.
In the last presidential election in 2012, Le Pen finished third with just under 18 per cent. She has tried to portray the 2017 contest as "David against Goliath".
She has worked assiduously to try to rid the party of its more extreme edge - and kicked her father out of it after he repeatedly described Nazi gas chambers as a "detail of history".
Over the past six years, Le Pen's rebranded "party of patriots" has been propelled by the anti-globalisation, anti-establishment fury that drove Britain's vote to leave the EU and Donald Trump's election in the United States.
Now a twice-divorced mother of three, she guards her private life jealously, in contrast to Macron.
She appears rarely as a couple with her current partner, who is the FN's vice-president Louis Aliot.
Le Pen developed her flair for sharp putdowns as a state-appointed lawyer defending illegal immigrants facing deportation.
Despite that experience she blames migration - and the European Union - for France's economic woes.
Watch: Le Pen campaigns in Northern France
The issues that divide Le Pen and Macron
Centrist candidate Emmanuel Macron and far-right candidate Marine Le Pen, who go head-to-head in the second round of France's presidential election on May 7, are diametrically opposed on issues ranging from immigration to Europe to gay marriage.
Here is where they stand on the key questions:
Le Pen has insisted on the need for France to drop the euro single currency and leave Europe's Schengen visa-free travel zone.
She says she will hold six months of negotiations on returning powers from Brussels to national capitals after which she will hold a "Frexit" referendum on France's membership of the European Union.
She also opposes the CETA trade deal between the EU and Canada.
Macron, a former banker and economy minister, has run an unabashedly pro-European campaign. He wants to bolster the eurozone by setting up a separate budget for the 19 countries that use the common currency.
He also proposes giving the zone its own parliament and finance minister.
Macron also wants Europe to strengthen its external borders by setting up a common border force, pool more of its defence forces and impose higher tariffs to protect European industry from unfair competition, particularly from China.
He is generally supportive of international trade deals and backs the treaty with Canada.
Le Pen has vowed a temporary "moratorium" on long-term legal immigration until quotas can be worked out. She wants to reduce net migration - the difference between the number of people arriving and leaving - to just 10,000 and bar illegal immigrants from gaining residency.
She would make it harder to qualify for asylum and curtail policies that let migrants bring relatives to France.
Foreigners convicted on terror charges or any other crime would be automatically deported, and she would abolish a law that allows children with migrant parents who are born in France to gain French citizenship.
She would also toughen laws on conspicuous religious symbols, extending a ban on Muslim head scarves, Christian crosses, Jewish skullcaps and other symbols to all public places. She would also ban the Islamic burkini swimsuit.
Macron has said he would not look to prohibit religious symbols outside of schools, nor ban the burkini. He has championed diversity and vowed to give tax breaks to companies that hire young people from tough predominantly immigrant neighbourhoods.
He has pledged to speed up the review process for asylum requests to a maximum of six months, including appeals.
He has praised German Chancellor Angela Merkel over her generous policy to asylum seekers that has seen more than one million new arrivals since 2015.
Labour and retirement
Both candidates have said they would keep France's official 35-hour work week, adopted by a Socialist government in 2000, but Macron, a liberal, has promised to give companies more freedom to negotiate working time directly with employees.
Le Pen wants to lower the retirement age to 60 years old from 62, while Macron wants to unify a complex web of retirement rules for various public and private-sector employees, while maintaining the current retirement age.
He also wants to give the self-employed access to unemployment benefits but suspend benefits for qualified workers who refuse two "decent" job offers.
To rein in the budget, Macron wants to cut 120,000 civil servant jobs, though hospitals would be spared, while also creating 10,000 police jobs and 4000 to 5000 teaching posts.
Le Pen advocates more civil servant jobs at the national level and for hospitals, but fewer jobs managed by French regional authorities. She also wants 21,000 more police and customs officials.
Le Pen would impose a 35-per cent tax on goods by companies that move production outside France, and also add a new tax on groups that hire foreign workers, as part of her "national preference" policy.
She would cut income taxes by 10 per cent for the lowest-earning households, and drop France's plan to withhold income tax from monthly earnings starting next year - currently the French pay tax on income the year after it is earned.
Macron wants a three-year suspension of residents' taxes for 80 per cent of French households.
He also wants to turn France's so-called "solidarity" wealth tax on people claiming more than 1.3 million euros ($1.4 million) in assets into a tax on real-estate wealth, which would exclude financial assets.
Le Pen has said she would leave the wealth tax untouched.
Energy, education, family
Macron has pledged to cut France's reliance on nuclear energy to 50 per cent of its total electricity needs by 2025, from about 75 per cent now.
Le Pen has been a staunch defender of nuclear power, and would halt France's efforts to develop wind power.
In education, Le Pen would impose a uniform for all public school students and roll back a controversial reform meant to make French school days shorter.
Macron wants to give schools more autonomy in terms of hiring and cut primary school class sizes in half in low-achieving and poor areas.
He would also ban the use of cellphones in elementary schools.
Le Pen wants to scrap a 2013 gay marriage law and replace it with a new form of civil partnership. She would also restrict medically assisted procreation to couples unable to have children naturally. Macron wants lesbian couples to also have access to fertility treatment.