We were surprised to discover that not much of Versailles was filmed in Louis XIV's famous palace of the same name.
Of course, it's a major tourist attraction nowadays, but that wasn't the only difficulty.
"The problem with the palace itself is that Marie Antoinette came after Louis XIV," explains producer Claude Chelli.
"And Marie Antoinette hated everything that Louis XIV did before her. She hated the furniture, she hated the walls. So she destroyed everything. There is nothing 17th century in there.
"She loved flowers so they adorn the walls it’s nothing to do with Louis. So we had to find other palaces around Paris to film in a real 17th century setup."
Below, Chelli reveals the sumptuous stand-ins...
"Vaux-le-Vicomte is a beautiful palace built by Nicolas Fouquet, who was Louis XIV's Minister of Finance. He built this beautiful palace and invited Louis XIV for a big party. Louis was so jealous that he put this guy in jail and stole the gardener and the architect to build Versailles!
"So it totally inspired Versailles in many ways. It’s much smaller than Versailles but it’s very beautiful."
Where? Maincy, 30 miles southeast of Paris in the Seine-et-Marne department
For more information, go to: vaux-le-vicomte.com
"Maisons-Laffitte is a big chateau that was actually built 30 years before Louis XIV moved his court to Versailles. It has beautiful ballrooms so we shot most of the parties and the dancing there. You'll also see its beautiful white staircase."
Where? Northwest of Paris, in the town of the same name in the Yvelines department
For more information, go to: chateau-maisons.fr
"There were 30,000 people living at Versailles in Louis XIV's time. It was huge. So we need to show the different ranks. Lésigny is a smaller and less fancy chateau, but we use it for the lower nobles quarters."
Where? Like Vaux-le-Vicomte, it's in the Seine-et-Marne department, 12 miles southeast of Paris in the town of the same name.
For more information, go to: chateaulesigny.fr
The Palace of Versailles
See if you can spot the scenes that really are shot in Versailles...
"The problem with Versailles is the gardens are open seven days a week, and the building is only closed on Mondays," says Chelli. "So we booked Mondays to shoot stuff that is so specific to Versailles, which was usually the Marble Court.
George Blagden as Louis XIV and Alexia Giordano as Nymphe in the Hall of Mirrors; main picture above: Blagden in the Marble Court
"Carriages would drive into the Marble Court and up to its beautiful gilded door where they'd set down their nobles. So we shot a lot of the arrivals there. It’s big and so beautiful.
"We also filmed in the Hall of Mirrors, the gardens and the Grand Canal – an ornamental lake, which reflects the sunset."
Where? In the leafy suburb of Versailles, about 14 miles southwest of Paris
For more information, go to: chateauversailles.fr
Versailles is on Fridays on BBC2 at 9.30pm