Dear movie producers: here is a movie pitch you can have completely free of charge. Consider it my gift to entertainment.
Opening scene: the night before her execution, Marie Antoinette finds a magic portal into the kind of future where space travel is a thing.
In this future, aliens are attacking, and she has to save France — nay, the entire human race.
She puts her knowledge of fashion to good use, and she impresses the aliens so much that they wind up worshiping us instead of murdering us.
The aliens (or future-humans, whatever) use their robot nanotechnology to make a non-feeling simulcrum that they send back in time to get guillotined.
Marie lives a long, healthy, happy, and fabulous life. She eats cake every day.