Gorgeous Carat

A Boys Love manga series by You Higuri (mangaka of Gakuen Heaven), set in Victorian era France. Currently a four-part series and a one-shot sequel, with more on the way.

Paris is in an uproar over the famous and notorious Phantom Thief Noir, aka usurer Ray Balzac Courland. A peniless aristocratic woman seeks Ray out to help with her family debts, and is forced to give him the only thing she can as collateral - her son, Florian du Rochefort. Their relationship starts off quite rocky, but this being BL, things run their natural course as the pair go on treasure hunting adventures, try (unsuccessfully) to fool the Private Detective bent on proving Ray's identity, and have run-ins with the crime syndicate Black Hand.

The main story is available in English from Tokyopop's BLU imprint, and the Gorgeous Carat Galaxy spinoff is licensed by DMP's Juné imprint.

Tropes used in Gorgeous Carat include:

Aw, Look -- They Really Do Love Each Other: The Ho Yay between the heroes isn't as blatant as other Boys Love series, but that just makes the sweet moments all the sweeter. Like Florian (and Ray, but it's not quite as poignant when he does it) willing to give his life for Ray. And Ray increasing Florian's debt so that he can never leave him.
Blood Brothers: Ray and Azura.
Break the Cutie
Cleaning Up Romantic Loose Ends: Poor Laila, so in love with Ray, starts to fall for his cousin near the end.
Crossdresser: Florian doesn't need makeup or a wig. Just a dress.
Cliché Storm
Dead Little Sister
Even the Guys Want Him: Florian. It's the eyes...
Everyone Is Bi: Characters' sexualities are never addressed (except for a couple 'are you gay?' jokes at Ray's expense). The guys just all want Florian.
Fingore: Florian gets a needle wedged under a fingernail during a torture session.
Heroic BSOD: Florian. Drugs and rape are bad.
Impoverished Patrician
Intimate Healing: Azura does the Medicine Kiss variation. That ain't medicine, though, and he ain't trying to heal.
Kick the Dog: Azura, many times.
Loan Shark: Averted and played with. Ray jokes about being this, but he goes out of his way to prevent Florian from being able to pay him back.
Love At First Sight: The relationship starts off quite one-sided. Ray just needed one look at those eyes. More of a 'desire for possession at first sight'.
No Sense of Direction: Very much Florian
Paper-Thin Disguise: Ray's disguise as Noir is a top hat and cape.
Parental Abandonment: Pretty much everyone.
Phantom Thief
Private Detective: Solomon Sugar.
Rape as Drama: Poor Florian.
Secret Identity
Sensitive Guy and Manly Man: Ray kicks ass and wields a mean whip. Florian also kicks ass, but he sure cries a lot.
Spoiler Opening: Manga variation. Azura's evil isn't much of a shocking plot twist when it's shown on that chapter's title page.
The Syndicate: The Black Hand.
Technicolor Eyes: Florian has amethyst eyes. For once, unusual eyes in a manga aren't treated as an everyday occurrence; they're commented on quite frequently.
Unlucky Childhood Friend: Poor Laila.
Whip It Good: Ray.
White-Haired Pretty Boy: Azura and his flowing silver locks. He is also dark skinned.
Will They or Won't They?: Ray and Florian aren't the type of couple to fall into bed together by the end of the first volume. They don't even kiss until the end of the fourth volume, and it isn't really shown. We're still waiting for outright declarations of love, and sex.
The Woobie: Eleonora is pretty batshit. But you would be too if, as a child, your mother was killed by your father, then your maternal uncle showed up and killed your father in front of you - and oh yeah, your maternal uncle is your real father. Uncle/father then molests you, and keeps you locked up with your dead mother. Whew.
~~Yaoi Fangirl~~Yaoi Fanboy: Ray and Azura embrace in a Muslim greeting. Everyone misunderstands. it is Noel, the five year old boy, who is squealing with glee, little hearts floating around him.