I have seen both Rose of Versailles and Le Chevalier D'Eon. The latter makes far more egregious historical liberties. If you view them as reconcilable with each other however, it could be viewed as a prequel to the former.
Both shows likely take influence from Alexandre Dumas. If not his own fiction depicting the French Revolution and it's lead in history, then his Swashbuckling adventures in general.
RoV had 40 episodes spanning 20 years. What struck me when I was done and looked back is how they managed to make it so, like in real life, you don't notice the characters ageing as it happens.
RoV leaves Cagliostro out of it's depiction of the Affair of the Diamond Necklace. D'Eon however prominently features Lorenza and Balsamo, as well as other figures prominent in the history of esoteric conspiracy theories, like Saint-Germain and sir Francis Dashwood.
The title character of d'Eon de Beaumont didn't have a sister historically, and was probably a Trans-Woman.
Both give historical villain upgrades to a number of figures. They have in fact similar approaches to the Duke de Orleans. There is an endless debate over whether the Duke was a true revolutionary or just seeking to make himself King. I don't see why he can't be a little of both. Theoretically the two Animes are not depicting the same Duke of Orleans, but historically Louis Philippe I was not tied to revolutionary movements. D'Eon is simply being anachronistic.
D'Eon contains supernatural elements which RoV does not. It's interesting because Dumas did not originally want to explain away the supernatural aspects of Joseph Balsamo, but editorial pressure made him.
Most of the Psalms recited in D'Eon are not true Biblical Psalms but constructed together from pieces of Biblical references. I recognized some of Psalm 2 at one point. Of course hearing a bunch of made up Bible passages about Vengeance set up an @$$kicking scene made me think of Pulp Fiction and Samuel L Jackson.
What's particularly interesting about D'Eon is what it does with Maximilian Robespierre, which I do not want to spoil.
RoV is in many ways most infamous for it's relationship to the Yuri Genre. Part of why overall I still like it better.