The audience stayed glued to their seats as Marco Bellocchio's new film about the 1978 kidnapping and killing of former Prime Minister Aldo Moro premiered at the festival on Thursday.
In Buongiorno, Notte (Goodmorning, Night) the historic events are seen through the eyes of a fictitious female kidnapper and member of the Red Brigades guerrilla movement named Chiara, played by Maya Sansa.
Rather than focussing on the many conspiracy theories linked to the murder, the veteran Italian director presents the audience with an intimate picture of the people caught up in the Red Brigades.
In particular, he looks at Chiara's everyday life, her dreams and ultimate doubts about the justice of their actions.
"Naturally, since I am not a historian I looked for a way, the most personal way, of making the movie," Bellocchio said in an interview. "That way, you also have the freedom to betray historical truth a little bit, putting off the inevitable."
In one particularly moving scene, Moro is "freed" by Chiara in a dream and walks smiling down a street. In reality, Italian authorities refused to negotiate with the guerrillas and after 55 days, Moro was found murdered in the boot of a car.
"Naturally, since I am not a historian I looked for a way, the most personal way, of making the movie"
Marco Bellocchio, film-maker
The film has thrilled critics in the lagoon city, where it has been touted as a strong candidate for the Golden Lion to be awarded on Saturday. "Goodmorning, Night" is one of 20 films - three of them Italian - vying for the top prize.
Bellocchio used the memoirs of a real female Red Brigades member and other historical texts to create his film.
"I am very critical," Bellocchio said. "They were absolutely insignificant people but they were terribly dangerous because they used the system of terrorism to kill."
The Red Brigades were responsible for a slew of murders of politicians more than two decades ago. The period was known as the "years of lead" because of the bullets that often littered Italian pavements after the attacks.
A letter written by Moro's son Giovanni praising the film's intimate scope was read aloud at a press conference. "I think this is a case when artistic creation will help people understand reality more," he said.
Bellocchio, 63, sparked a storm at Cannes last year when he presented "My Mother's Smile" about an atheist whose murdered mother has been proposed for sainthood.