With director David Wnendt, Masucci travelled around the country by car for a month, interacting with ordinary people while dressed as the Nazi leader and filming the results with two cameras.
"They forgot relatively quickly that the two cameras were running and began to pour their hearts out to this man, to say what was really on their minds," Masucci told ARD public television.
"And then shortly afterwards we saw that in the Pegida movement, that didn't surprise us that they suddenly went into the streets. Because this middle-class that's swinging to the right, we'd already seen all that on camera."
After Pegida ("Patriotic Europeans against the Islamization of the West") burst onto the national scene with increasingly large anti-Islam demonstrations in Dresden, they were often referred to as "Pinstripe Nazis" by commentators because of the movement's predominantly middle-class participants.
Not just Dresden
But the phenomenon was far from restricted to Dresden or the former communist east German states, Wnendt told ARD.
Rather than insulting Hitler or confronting him, people seemed happy to see and chat with the man behind history's most infamous genocide.
"By the end of our filming, our questions had totally changed. How can it be that so many people react so positively to Hitler, accept him like that?" he asked.
The pair pointed to one incident when they paid an actor to shout anti-Germany slogans among football fans in Berlin during the 2014 World Cup.
He was set upon by a violent group and Wnendt had to call security "so that he didn't end up hung from the nearest tree".
"We wanted to see if you could escalate something like that, if it works. And sadly it did work," Masucci said.
Wnendt's film – in cinemas on Thursday - is based on the 2012 book of the same name by comic Timur Vermes, which imagines the consequences after Hitler wakes up hale and hearty in Berlin in 2011.
By force of will and the public's ability to find him funny rather than terrifying, he gradually gains a fanbase for his own TV show and online presence.
Critics were divided in their reaction to the book, with Die Zeit calling it "shockingly plausible" while the Süddeutsche Zeitung argued that it "had a trivializing effect by showing Hitler as a funny guy".
By August 2015, the book had sold more than two million copies in German as well as 300,000 audiobooks, and was being licensed for publication in more than 40 countries.