The darker side of ballet...
There’s something big that the movie doesn’t mention, understandably so.
Back in the 19th century, ballet wasn’t as glamorous as we might think, and in fact was considered by many as simply a high end brothel.
Théophile Gautier said, “The young ballerina is at once corrupt as an old diplomat and as naïve as a good savage. At the age of thirteen, she could teach a courtesan.”
It’s a bit of an exaggeration, but the truth is that many patrons of the ballet, known as abonnes (meaning ticket-holders or subscribers) took on ballerinas as mistresses. This is especially true because most of the dancers came from poor families, and while they did receive a stipend it often wasn’t enough to survive. Securing a patron was better than becoming a prostitute (and many did that), and it was a way for them to improve their lives.
Of course, back then it wasn’t seen as powerful men abusing their positions, but immoral girls seducing men to better themselves. While there was a certain glamor of being a dancer at the Paris Opera, it wasn’t a secret what was going on behind the scenes.
Now what does this all mean for the movie?
Easiest thing would be to assume the movie is an AU where this stuff didn’t happen.
But if it DID happen, then I think the most interesting aspect would be Camille. Why is her mother so determined to have her daughter become a dancer when they’re already well off?
One theory is that Mme Le Haut hopes to gain more prestige through her daughter and further climb the social ladder. Or perhaps she was once a dancer herself and is living vicariously through her daughter (which is apparently pretty common modern day).
Unfortunately, this isn’t just a relic of the past. A ballerina from Russia’s Bolshoi theater revealed in 2013 that this exploitation of the ballet dancers was/is still a part of the ballet world. (source)