A cotton tycoon first elected to lead the West African nation in 2016, Talon faces two little-known rivals, Alassane Soumanou and Corentin Kohoue.
Most opposition leaders are in exile, have been disqualified by electoral reforms or targeted for investigation by a special court.
Once praised as a vibrant democracy in an often troubled region, tensions were on the rise ahead of the vote, with protests breaking out in several cities.
“The particularity of this election is that it is taking place in an atmosphere of tension and violence,” a platform of civil society said in a statement Saturday.
In central and northern Benin, protesters blocked hundreds of cars and trucks travelling between the coast and the north.
On Thursday, in the central city of Save, two people died and five others suffered gunshot wounds after troops fired tear gas and live rounds in the air to break up a demonstration.
“I don’t understand what Talon is doing… if the president has issues with opponents, he should spare the people,” said Philomene M’Betti Tepa, a resident of the northwestern town of Boukoumbe.
Talon’s backers have rejected accusations the election will be fixed, saying all the conditions are there for a fair vote.
The electoral commission’s president Emmanuel Tiando told AFP Saturday that despite delays in dispatching electoral material to the north, there was “nothing preventing this election from taking place”.
More than 4,9 million people are eligible to vote across 15,531 polling stations.