UPDATE (Sunday, 6:05 p.m.): Agence France Presse reports that Anne Hidalgo has been elected the first female mayor of Paris. The news agency said that she won by an “unexpectedly” comfortable margin on a day when her party, the ruling Socialists, were routed in other municipal elections around the country, which was attributed to the unpopularity of President Francois Hollande’s government.

PARIS — The French capital is poised to elect its first female mayor this weekend. This historic event was to have taken place after last Sunday’s municipal elections, which Socialist front-runner and deputy mayor Anne Hidalgo was expected to win.

But she was upset by another top-tier candidate, who also happens to be a woman, Nathalie Kosciusko-Morizet, a center-right contender from a prominent political family.

Since neither received more than 50 percent of the vote, they will face off on Sunday. The new madame le maire will take over one of the world’s most fabled cities, which, like most other major cities, also is facing economic, social and environmental challenges. The new female chief executive will run a metropolis that is home to more than 2 million people and oversee a $10.5 billion budget and more than 50,000 employees.

Kosciusko-Morizet made a point of taking the Métro after her surprise showing last weekend, a victory lap of sorts  as well as a continued effort to present herself as a woman of the people. Hidalgo, meanwhile, has been busy meeting with members of other political parties, hoping to secure their backing.

Polls had shown Hidalgo, 54, as the clear leader in a crowded field of candidates. But, Kosciusko-Morizet, a protégé of former president Nicolas Sarkozy, unexpectedly won 35.64 percent of the vote to Hidalgo’s 34.4 percent.

Kosciusko-Morizet, 40, is not new to politics. Her grandfather, Jacques Kosciusko-Morizet (born Kosciusko), was an academic and former French ambassador to the United States whose father-in-law, André Morizet, was the mayor of Boulogne-Billancourt. Her father, François Kosciusko-Morizet, is the current mayor of Sèvres.

She knows what is at stake in this race. To become the first female mayor of Paris would be an exciting addition to her family’s legacy. She startled many by winning the first round, but can Kosciusko-Morizet, who is commonly referred to as NKM, persuade voters to come out and support her again?

The newspaper le Parisien and other media continue to predict that Hildalgo will win Sunday.

Both Hidalgo and Kosciusko-Morizet made gaffes during their campaigns, although Kosciusko-Marizet’s have generated more attention. She has been ridiculed for trying to portray herself as “everywoman,” an average Parisian, just like everyone else.

In one incident, Kosciusko-Morizet rode the Métro in Paris with cameras rolling, explaining to Elle Magazine: “For me, the métro is a charming place, anonymous but at the same time familiar … I often take lines 13 and 8 and I’ve had some incredible encounters.” Critics were quick to note that line 13 is one of the most crowded Métro lines in the city. Most Parisians would not consider it charming.

Then there was the Vélib’ incident, in which she was photographed using a two-wheeler from the bike-sharing service to ride around Paris. Unfortunately, someone pointed out her $2,700 Bottega Veneta handbag in the front basket.

Kosciusko-Morizet is seen as aloof, in part because of her upper-class roots. She graduated from some of France’s most elite schools, including a private Catholic school, and the prestigious École Polytechnique and the Collège des Ingénieurs.

In 2002, she became a member of parliament. In 2007, she was made a secretary of state for ecology, and in 2010 was promoted to minister for ecology, sustainable development, transport and housing, one of the top cabinet posts. She was the mayor of the Paris suburb Longjumeau until this year.

In the current campaign, Kosciusko-Morizet has said she would reduce the number of city civil servants to save $310 million by 2020. She also wants to expand pedestrian space in the city and improve public safety. She would ban the most polluting vehicles, especially trucks and tourist buses, and extend the Métro until 2 a.m. during the week. She also has generated buzz by proposing sumptuous makeovers of abandoned Métro stations in Paris.

Hidalgo has been deputy mayor of Paris for the past 13 years, serving in the administration of the current mayor, Bertrand Delanoë.  She, too, has been criticized for some campaign blunders, including showing up for events in a tiny Smart Car and a campaign poster featuring a glamorous portrait that one critic likened to an ad for anti-wrinkle cream.

She has a compelling personal story: She moved to the city of Lyon in 1961 with her parents from Spain when she was just 2 years old. The family lived in social housing, and Hidalgo pulled herself up the rungs to become one of the most successful women in Paris.

In her campaign, she has called for an “investment program” of $11.7 billion in the city, but with no increases in taxes. She has said she plans to build 10,000 new homes a year and provide better public transport and more green spaces. She would close off Paris to diesel vehicles by 2020 and provide a free moped system called Scooterlib’ and extend the Métro. She would also add 5,000 new day-care spaces, a major issue in Paris for thousands of families who can’t find affordable day care.

Regardless of which candidate gets the most votes on Sunday, women in Paris have already won. Although Madrid has had Anna Botella at the helm since 2011, and Washington, D.C. and Sao Paulo have had female mayors, only a few of the world’s major cities have been run by women. Parisians are about to add to the list.

Although France passed a law in 2000 requiring gender parity among candidates, it still ranks low in global comparisons of women’s political empowerment. The United Nations’ 2012 Global Gender Gap survey placed France at 63 in the world, between Ethiopia and Chile. More than 80 percent of parliamentary seats are held by men, and only a handful of the French towns with populations over 100,000 have female mayors. Electing the first female mayor in Paris will be a step toward equality in the political arena.

Priscilla Lalisse-Jespersen is the editor and founder of Prissy Mag, an Anglophone Webzine about life in Paris as an expat, and the author of “Stockdale” and “Next of Kin.” Find her page on Facebook.