Some surveys have been predicting a turnout closer to the 70% that took the National Front's then-leader, Jean-Marie Le Pen, into the second round in 2002.
BFMTV and Elabe suggest scandal-hit conservative François Fillon and far-left wildcard Jean-Luc Mélenchon secured 19.9% and 19.3% of the vote respectively, and have been knocked out of the closely-fought race.
French and European equities were expected to rally when they begin trading on Monday morning, while peripheral bond yields were expected to fall as investors regained their risk appetite. If she were successful, it would probably sink an institution that has helped bind Europe together for decades.
French media have also accused conservative party candidate Francois Fillon of financial links between his campaign and the Russian government, allegations that Fillon disputes.
Macron, a former banker and independent candidate, has been atop the polls - along with far-right candidate Marine Le Pen - but has seen his popularity slip a bit in advance of Sunday's elections.
Throughout the campaign, Macron insisted France was "contrarian" - ready to elect a pro-globalisation liberal at a time when rightwing nationalists are making gains around the world.
In a victory speech, Macron told supporters of his fledgling En Marche!
Le Pen moved quickly after the shooting to present herself as the strongest defender against Islamist extremists, calling for France to "immediately" take back control of its borders from the European Union and deport all foreigners on a terror watchlist.
Socialist candidate Benoit Hamon told supporters his party had suffered an "historic blow" from its voter base and called on voters to back Macron and reject Le Pen in "the strongest possible way". It puts on me a huge responsibility to defend the French nation, its unity, its security, its culture, its prosperity and its independence. "You will get a France that protects the people, we will not have the free circulation of terrorists".
"Today as yesterday, I am delighted that France is a mix of races and all the children are our children", he has said.More news: Ben Wheatley on Free Fire
But he has has never held elected office - he served as economy minister under Hollande before resigning previous year - and his lack of experience, lack of established party and youth could count against him.
With two anti-globalisation candidates whose policies could break up the European Union among the four front-runners, the vote is of major significance to the worldwide political status quo and to investment markets.
Macron topped Sunday's first round with 23.7 percent of votes, slightly ahead of National Front (FN) leader Le Pen with 21.9 percent, according to near-final results from the interior ministry.
In an American-style move unusual in French politics, Macron appeared on stage hand in hand with his wife, Brigitte, both waving at the crowd with tears in their eyes.
Surveys suggest that almost a quarter of voters are still undecided and that until now the French have been more concerned about jobs and the economy than terrorism.
But after Brexit and the election of U.S. President Donald Trump, his first round victory - which comes after setbacks for far-right politicians in Austria, the Netherlands and Germany in recent months - shows that the political center is holding in the heart of Europe.
Political analysts say Macron's apparent win today showed that many French people still believe in a more liberal, open, global society even as populists have won big victories in the a year ago with the United Kingdom's vote to leave the European Union and Donald Trump's election in the United States. Voters overseas could also cast ballots in French embassies on Saturday.
Polls show that Le Pen may face an uphill battle against Macron on May 7th - all head to head polls show Macron with a comfortable lead.
When Macron spoke Sunday, he sought to distance himself from that accusation, despite the fact that Hollande called him Sunday night to congratulate him on qualifying for the second round of voting.
To view PDF documents, Download Acrobat Reader.