At the end of the movie, the old lady says, "My great grandmother's portrait hung in the university up until the revolution. By then the truth of the romance had been reduced to a simple fairy tale."
Here's where we need to do a little math...
The Brothers Grimm wrote Cinderella in 1812. They were visiting the old woman.
The French Revolution started in 1798. We're okay so far.
Let's say she looks about 70, give or take a decade.
Let's also say that each mother was 40 years old on average when they gave birth to their daughter (very generous, since human life expectancy at that time was less than 40 years!).
It looks like this:
Person Year Born
Her mom 1700
Her grandma 1660
Her great grandma (Danielle) 1620
Of course, they spend a lot of time hanging out with Leonardo Da Vinci, who died in 1519.
There's 100 years we need to account for.
Perhaps her "Great great great great great grandmother's painting" hung in the university!