According to Wikipedia, the movie had thousands of costumes and lavish set designs. Adrian visited France and Austria in 1937 researching the period. He studied the paintings of Marie Antoinette, even using a microscope on them so that the embroidery and fabric could be identical. Fabrics were specially woven and embroidered with stitches sometimes too fine to be seen with the naked eye. The attention to detail was extreme, from the framework to hair. Some gowns became extremely heavy due to the embroidery, flounces and precious stones used. Norma Shearer's gowns alone had a combined weight of over 1,768 lb., the heaviest being the wedding dress.
MGM's recreation of the ballroom at Versailles was twice as large as the original.
Marie Antoinette's famously-high coiffure is shown adorned with a miniature diamond-studded bird cage complete with a canary that tweeted when she pulled a hidden string. This adornment was in fact worn by the Grand Duchess of Russia at a 1782 party that Marie Antoinette hosted at Trianon. The Duchess's bird not only chirped, but its wings also flapped with the tug of a thin gold chain.
This film features only two of Marie Antionette and Louis XVI's children. They in fact had four children. Their first son, Louis-Joseph, died at the age of eight of TB. In 1785 Dauphin County, Pennsylvania was named for him as a thank you to France for helping America win its independence. Their last child, Sophie Helene Beatrice, died before her first birthday.
From its initial inception up until right before the cameras started to roll, the film was designed to be shot in Technicolor. All of the sets and costumes were designed with color in mind. MGM went as far as to send the fox cape that Norma Shearer wears (to see Henry Stephenson on the night she becomes Queen) to New York to be specially dyed to match the blue of her eyes. Fearing that the addition of Technicolor would swell the already mammoth (for the time) $1.8-million budget, the production went before black-and-white cameras instead.