Why is the Nazi flag flying in the French city of Nantes?

Social media users are sharing images of the Graslin Theatre in Nantes, western France, covered in Nazi flags. Some of the posts include outlandish claims that the city is under occupation or invasion, while others describe a bizarre atmosphere in the air.

Others show old-style cars, or seemingly portray Nazi soldiers in the city.

• Fact-check: Did an Israeli company sell a bloodied doll of a Palestinian child?

• Has the Eiffel Tower caught fire?

• Is the Las Meninas painting being cancelled for being a hate crime?

The pictures are indeed real, but any claims on social media that the flags' presence is due to some sort of "invasion" or "leftist and Islamist" plot are not.

Rather, production company Rezo Productions has been filming its new fantasy series "Deep" in the city.

Set in 1941, the series tells the story of a newly occupied France which discovers that the Third Reich has developed a new type of submarine that can travel through time.

There are various clues that prove the Nazi flags in Nantes were all part of a set. In some of the shots, you can clearly see camera crews, lights and cranes – and what's more, a quick Google search will also show that the whole thing is being widely reported by French media.

Some of the stories act as a warning so that people are aware of what’s going on, while others report on citizens' reactions.

For good measure, The Cube got in contact with Nantes' town hall, who confirmed that the flags are indeed in the city as part of a shoot.

Nantes under the Nazis

The Nazi occupation is a firm part of Nantes' history, following the fall of France.

During the Second World War, German troops entered and conquered the city, taking control in June 1940.

Camps were set up around Nantes for prisoners of war – but the city also played host to small resistance groups.

A key moment in the Nazi-occupation of Nantes was the execution of 48 civilians in 1941, in retaliation for the assassination of German officer Karl Hotz.

They are known as the "50 hostages", because the Nazis originally planned to kill 50 of them.