It's certainly an entertaining book, and I had fun reading it, but wouldn't say it was necessarily good. More like so-bad-it's-good, but I'll start with what I liked.
This book is set during the Reign of Terror and the French Revolution. I found the politics interesting. Never could I imagine a trashy erotic novel from the 80s would have me sympathetic to the aristocracy, but here we are.
The spicy scenes were spicy, albeit repetitive (take a shot everytime the author says "twin globes" instead of breasts. or how about everytime they kiss he "explores every secret crevice in her mouth" -- what is he doing, licking her molars? gross.) -- Still, I found myself giggling and blushing at a few points. Extremely flowery language that draws out every detail and emotion, very different from modern smut.
I also liked the lengthy descriptions of historical fashion and architecture, but I would understand if other readers found it boring, because it's a lot, I just like historical fashion and architecture.
Unfortunately, the pacing is all over the place, which is why I have to give it two stars. Many interesting pirate things happen "off screen" while other superfluous details span pages and pages. Like when Justin and Genevieve go to a party. They could have had a cheeky, flirty conversation while ballroom dancing, I would have enjoyed that. Instead the whole scene is used to bring up "Rouge et Noir," a popular card game at the time and also the main characters nicknames. We're supposed to think that's clever.
My biggest gripe is that the stakes felt artificially high. Genevieve spent the novel trying to rescue her parents from the guillotine, but in the last few pages they manage to escape by themselves. Quite easily, in fact, so the entire crux of the novel is resolved in just a paragraph or two. So she could've just sat on her ass the whole time and things would've worked out fine.
Another example: when Justin discovers that his lover is actually is wife (you must suspend your disbelief to enjoy this book) he comes up with one ridiculous reason after another to avoid "coming out" to her. he even asks her to choose between himself or... himself. So many times I thought "here is where it all comes out, right? nope." The tension was needlessly dragged out until, again, it is resolved quickly and stupidly in the last few pages.
There is a second mistaken-identity-romance subplot between Vachel and Kitty. At first I found this interesting but it ultimately went nowhere and is -- you guessed it -- resolved at the very end without any fanfare.
There is also a lot of problematic tropes, which I can easily blame on the time period when it was written. For example, Noir can feel her hymen breaking when he takes her virginity. He later goes on to say most women aren't so obvious but Genevieve's pussy is especially tight (paraphrasing here.) I laughed out loud at that part. You're telling me she's beautiful, skinny, intelligent, chaste, brave, unique, excellent with a sword, AND her pussy is ungodly cinched!? Talk about a Mary Sue.
There are two scenes that are fairly sexy but fairly rape-y. The characters even address it, but ultimately decide it's not actually rape because Genevieve comes (get it?) to enjoy it. Also she's 16, but I chose to ignore that because she's pretty badass. Until a man starts kissing her, that is. Also, they're cousins from identical twin mothers. Ignore that part too. Ultimately it was a fun, trashy book, but you have to be extremely forgiving in order to enjoy it.