In hindsight it might have been a good idea for authorities in Nice to alert the public that a film about the Nazis was being made in town.
On Monday passersby were left speechless when an enormous Nazi banner was draped over the Palais de la Prefecture, a government building in Nice's Old Town.
A witness said that people were unsure if it was intended as a joke or to deliberately provoke the bystanders.
“As soon as two men appeared on the roof to unfurl the banner, a crowd started to shout,” the bystander told the Nice-Matin newspaper
“Obviously it caused some strong feelings.”
Another witness, Andrew Gentry, told the BBC that the scene was surreal.
“People started screaming… they were really agitated,” he said.
“There was nothing around to explain what was going on. The scene was just surreal.”
Others saw the humorous side.
Initially surprised when they saw the large flag from afar, German tourist Mathias and his son Tobias later sent pictures of it to their friends back home joking: “We are back!”
Later in the day, local authorities were forced to issue a statement to reassure locals that the banner was nothing more than a prop for a film being made in the area, which is based on World War Two and directed by Canadian Christian Dugay.
And on Tuesday a large yellow signboard read “film set” and “historical reconstruction” to dispel any further confusion.
The film, entitled “Le sac de billes” (A Bag of Marbles), is based on the memoirs of Joseph Joffo who fled Nazi-occupied Paris as a child.
The Palais de la Prefecture in Nice was being used as a replacement for the nearby Hotel Excelsior, which was actually used as a spot to round up Jewish people before taking them to the death camps during the war.