Tunisians are voting to choose a new president, in a decisive final-round vote between two political newcomers: a flamboyant media mogul and a conservative law professor.
Tycoon Nabil Karoui and retired academic Kais Saied swept aside a host of establishment candidates in the first round of voting last month.
Mr Karoui, 56, has campaigned from prison after being arrested on charges of money laundering and tax fraud.
He denies the charges.
Mr Karoui, who was freed by a court order just four days ago, came second in the first round of voting, with 15.6% of the votes to Mr Saied’s 18.4%.
Tunisia’s electoral commission has said that if Mr Karoui loses the run-off election he could appeal the result as he has not been allowed a fair campaign.
The two outsiders saw off a crowded field of 24 other candidates in the first round, striking a blow to Tunisia’s political establishment.
Prime Minister Youssef Chahed and former interim President Moncef Marzouki failed to progress as voters showed their frustration with a stagnant economy, high unemployment and poor public services.
What are the two candidates offering?
A 61-year-old law professor nicknamed “the robot”, Mr Saied has run a shrewd and hard campaign, with almost no advertising, on a message of integrity and anti-corruption targeted at young Tunisian voters.
In the week before the polls, he announced that he would not campaign while his rival was in prison.
He has promised electoral reforms, including changes to local elections for regional representatives.
Critics have attacked his conservative social views, however.
In an interview with a local newspaper, he accused foreign powers of encouraging homosexuality in the country.
He is in favour of returning the death penalty, suspended since 1994 in Tunisia, and has said that if he wins the presidency, his wife will not be the country’s first lady.
As for Mr Karoui, he is dubbed Nabil “Makrouna” (pasta) for his charity’s distribution of money and bags of the staple food.
Supporters view him as a self-made businessman whose philanthropy is praised in a country facing rising living costs and youth unemployment.
He founded the charity to fight poverty – a central theme of his campaign.
Opponents have also accused him of using his popular TV station, Nessma, to further his political ambitions.
He was arrested in August on charges of tax evasion and money-laundering shortly before the campaign opened.
The charges have not been dropped, despite his release from prison.
His supporters accuse powerful forces in the country of conspiring to scuttle his candidacy, but authorities say his arrest was based on a three-year-old investigation.
What is the significance of the poll?
The election was brought forward after the death in July of Tunisia’s first democratically elected president, Beji Caid Essebsi.
He took office in 2014, three years after a popular uprising that led to the overthrow of long-serving ruler Zine al-Abidine Ben Ali, and sparked the Arab Spring.
Correspondents says that while the Arab Spring gave Tunisia democracy eight years ago, many believe it brought little else.
And Djordje Todorovic, a foreign observer at the poll, said he was concerned that Tunisia “probably won’t have a strong or stable government after this election”.