SEOUL, South Korea — Eom Hang-ki’s pizza parlor in the run-down Noryangjin district of Seoul has attracted unusual customers in recent months: movie fans from Japan and even the United States and Argentina, all coming to pay homage at one of the locations where Bong Joon Ho shot “Parasite.”

“I am so happy that my shop played even a tiny role in the creation of the historic movie,” Ms. Eom, 65​, said of the film that has become a worldwide sensation and this week became the first foreign language movie to win the best picture Oscar. “But frankly, I was confused at first when foreigners began showing up at my shop.”

The streets of Seoul are as much a character in “Parasite” as the actors themselves, and they played a formative role in shaping Mr. Bong’s politicized worldview and intense focus on the searing inequality in the pulsing city of 10 million people.

Mr. Bong’s relatives have told the South Korean news media that he showed a keen attention to wealth disparities from an early age, bringing poorer friends from school home to dine with him. When he was at Yonsei University in Seoul, students championed the rights of the poor and underprivileged, often going to rural villages as volunteer farmers and teachers during summer vacations or infiltrating work sites to help organize unions.