The film was nominated for both the Academy Award for Best Writing (Original Screenplay) and the BAFTA Award for Best Film from any source. It was the most popular Italian film at the box office in 1945-46, finishing ahead of Mario Mattoli's melodrama Life Begins Anew.
During the Allied invasion of Sicily, an American reconnaissance patrol makes its way to a Sicilian village at night. Only one of the Americans speaks Italian. Local Carmela (Carmela Sazio) agrees to guide them past a German minefield. They take shelter in the ruins of a seaside castle.
While the others take a look around, Joe (Robert Van Loon) is assigned to keep an eye on Carmela. Despite the language barrier, Joe starts to overcome her indifference. However, he is shot by a German sniper. Before the small German reconnaissance patrol reaches the castle, Carmela hides Joe in the basement. When the Germans send her for water, she sneaks back and checks on Joe, only to find him dead. She takes his rifle and starts shooting at the enemy. The Germans throw her off a cliff to her death and leave. When the Americans return, they find Joe's body and assume Carmela killed him.
The Allies invade mainland Italy and capture the port of Naples. An orphaned street urchin named Pasquale (Alfonsino Pasca) happens upon Joe (Dots Johnson), an embittered, completely drunk African-American soldier. When Joe falls asleep, Pasquale takes his boots. The next day, Joe, a military policeman, nabs Pasquale in the act of stealing supplies from a truck. Joe demands his boots back, but when the boy takes him to where he lives, the sight of the squalor causes Joe to leave without them.
Fred (Gar Moore) is a drunken American soldier in liberated Rome. A young woman, Francesca, takes him to her room, hoping to earn a little money through prostitution. He is not interested and tells her of his futile search for a young woman he met and fell in love with shortly after the liberation of the city, six months before. As he describes the woman, Francesca realizes that she is the woman; both of them have changed so much in the short time that has passed, they did not recognize each other. Francesca says she knows the woman. When Fred falls asleep, Francesca slips out, asking the building superintendent to give Fred a slip of paper with her address on it when he awakes and leaves. Fred assumes the address is that of a whorehouse, throws the piece of paper away and leaves the city with his unit. The next day, Francesca waits in vain in her apartment.
The southern half of Florence is freed, but fierce fighting continues in the other half, across the Arno river, between Italian partisans and the Germans and their die-hard fascist allies. All the bridges except the Ponte Vecchio have been blown up, stalling the Allied advance. American nurse Harriet (Harriet Medin) is frantic to get across and be reunited with a painter.
She learns that he is now "Lupo", leader of the local partisans. She and partisan Massimo (Renzo Avanzo), a man desperate for news of his family, risk their lives and cross into the still-occupied city through the supposedly secret Vasari Corridor, which when Rossellini filmed it was still mostly empty of its art collection. Harriet is devastated to learn that Lupo has been killed.
Three American chaplains are welcomed to stay the night at a newly liberated Roman Catholic monastery. Captain Bill Martin (William Tubbs), who is the only one of the chaplains who speaks Italian, acts as interpreter. The monks are dismayed to learn from Martin that only he is a Catholic; his two colleagues are a Protestant and a Jew. When the guests and their hosts sit down to supper, Martin observes that the monks have nothing on their plates. He inquires and learns that the monks have decided to fast in the hope of gaining the favor of Heaven to convert the other two to their faith.
In December 1944, three members of the OSS are operating behind German lines with Italian partisans in the Po delta. They rescue two downed British airmen, but run out of ammunition in a battle with the enemy and are captured. The partisans are summarily executed the next day, as they are not protected by the Geneva Conventions. Two of the outraged prisoners of war are shot when they try to interfere.
After the enormous international success of Rome, Open City, Rossellini was able to obtain funding from international investors, particularly in the U.S. He decided to make a film about the liberation of Italy from the Allied invasion in 1943 to the end of World War II in 1945. Unusually for a film with much dialogue not in English, Metro-Goldwyn-Mayer took over distribution of the movie in the United States (from smaller firm Burstyn & Mayer), helping its visibility.
Rossellini engaged six writers, each of whom was to write one episode: Klaus Mann, Marcello Pagliero, Sergio Amidei, Federico Fellini, Alfred Hayes, and Vasco Pratolini. Each episode took place in a different location. The script notwithstanding, Rossellini often improvised with the actors and rewrote the stories as they were being filmed. For the first episode filmed in Sicily, Rossellini discarded the script and coached the non-professional, illiterate lead actress Carmela Sazio to a performance that received critical praise.
Bosley Crowther of The New York Times hailed it, writing it "marks a milestone in the expressiveness of the screen." He went on to say "It is useless to attempt an explanation, in familiar and concrete terms, of its basic theme and nature, for it is not an ordinary film—neither in form nor dramatic construction nor in the things it has to say", "the antithesis of the classic 'story film'". He ended his review with "This is a film to be seen—and seen again."
Jóse Luis Guarner praised the first episode, stating that the camera "keeps still throughout the long conversation, content to look and record, like a film by Louis Lumiere. A lot more is suggested than can actually be seen: the soldier's loneliness, his need to talk to someone, his longing for home and family, the girl's growing confidence...to show all this with such economy of means is one of the greatest secrets of the cinema. The whole of Paisà witnesses the same pressing need to portray a complex reality directly, at one go." Guarner went on to call it "Rossellini's first masterpiece, a masterpiece of neorealism as well as one of the peaks of film history."
Andre Bazin wrote that "the unit of cinematic narrative in Paisà is not the "shot", an abstract of a reality which is being analyzed, but the "fact": A fragment of concrete reality in itself multiple and full of ambiguity, whose meaning emerges only [afterwards] ... thanks to other imposed facts between which the mind establishes certain relationships." Robin Wood praised the film's newsreel footage-like style in adding to the realism and compared the scene of peasants being rounded up in the Po Valley to the Odessa Step sequence in Battleship Potemkin.
TV Guide called it "perhaps Rossellini's greatest achievement", "a wartime portrait full of humor, pathos, romance, tension, and warmth", and "a film unlike any other the world had seen". "PAISAN highlights the power of the neorealist style better than almost any other film."
The Chicago Reader's Dave Kehr observed that "The episodes all seem to have an anecdotal triteness ... but each acquires a wholly unexpected naturalness and depth of feeling from Rossellini's refusal to hype the anecdotes with conventional dramatic rhetoric."
Richard Brody of The New Yorker noted that "the sketch-like format of the six-part Paisan, from 1946, enabled him to mix actors and nonactors, to film in sequence and improvise his stories as he went along, and to use newsreel-style camerawork."
All eight Rotten Tomatoes reviews are favorable toward the film. Director Martin Scorsese has also listed it as one of his favourite films of all time and his all-time favorite of the Rossellini films.
Roberto Rossellini's film would inspire future directors, such as Italian Gillo Pontecorvo, to become filmmakers themselves. Later, Pontecorvo would create films, like Battle of Algiers (1967), in which he adopted Rosselini’s techniques of using non-professional actors and real locations.