The seven men and one woman standing trial in Paris are accused of crimes ranging from being aware of his intentions to providing logistical support and supplying weapons.
Of the accused, three suspects are charged with association in a terrorist conspiracy and the five others with association in a criminal conspiracy and violating arms laws.
Only one suspect, Ramzi Kevin Arefa, faces the maximum penalty of life imprisonment if convicted as a repeat offender. The others risk between five and 20 years in prison.
Of the accused, only seven will appear in court after one suspect, Brahim Tritrou, being tried in absentia, fled judicial supervision to Tunisia where he is now believed to be under arrest.
Just three of the accused are currently under arrest with one held in connection with another case. The defendants are a mix of Tunisians, French-Tunisians and Albanians.
The attacker, a 31-year-old Tunisian named Mohamed Lahouaiej-Bouhlel, was shot and killed by police after a four-minute rampage down the seaside embankment of the Promenade des Anglais.
"We're waited six years for this," Seloua Mensi, whose sister, aged 42, was killed in the attack, told AFP in Nice. "The trial is going to be very difficult for us, but it's important to be able to speak about what we went through.
"Confronting the accused, seeing them and understanding what happened, will allow us to rebuild our lives," she said.
The Nice trial is taking place at the historic Palais de Justice in Paris, in the same purpose-built courtroom that hosted the November 2015 attacks hearings. A special venue has also been set up in Nice to allow victims to follow proceedings via a live broadcast.
Some 30,000 people had gathered on the seafront to watch a fireworks display celebrating France's annual Bastille Day holiday on July 14, 2016 when Lahouaiej-Bouhlel began his rampage.
Nice was struck again in October 2020 when a Tunisian Islamist radical stabbed three people to death at a church.
Nice's right-wing mayor, Christian Estrosi, said: "This wound will never heal, whatever the outcome of the trial. This wound is too deep."
According to French and Tunisian press reports, the body of Lahouaiej-Bouhlel was repatriated to Tunisia in 2017 and buried in his hometown of M'saken, south of Tunis. This has never been confirmed by the Tunisian authorities.