[UPDATE: After some digging, help from Twitter and updated information, it seems this story is most probably bogus.]
So far, Christopher and Jonathan Nolan have been tight-lipped about the villain(s) facing off against the Caped Crusader in Batman 3. A casting grid leaked last July indicated that The Riddler will be the antagonist in the third Batman film, but no new information has emerged since then.
Now, an intriguing casting rumor has popped up in the wake of Chris Nolan's official confirmation as the director of Batman 3 and it involves his Inception star, Marion Cotillard. The French actress was reportedly offered but declined not one, but two roles in Batman 3 - specifically, that of either Selina Kyle (a.k.a. Catwoman) or Talia al Ghul, the daughter of the now-deceased Ra's Al Ghul from Batman Begins.
There has long been speculation that Catwoman would appear in Nolan's third Batman pic, with the likes of Angelina Jolie and Emily Blunt rumored at one point as possible candidates to play the sleek anti-heroine. An Oscar-winner like Cotillard would certainly be a major contender for the role, even if she had not already worked with Nolan on his previous film.
ComicBookMovie broke the story that Cotillard turned down the offer to appear in Batman 3 - due to concerns about the planned shooting schedule for the project. The site has since removed that report, apparently at the behest of Warner Bros. - that alone strongly indicates that there is more to this story than just idle speculation.
Catwoman has been brought to life by many different actresses over the years, including that of Julie Newmar, Lee Meriwether, Eartha Kitt, and Michelle Pfeiffer (yes, we are intentionally ignoring Halle Berry's incarnation of the character). The sinewy and gymnastic cat burglar is without a doubt the Caped Crusader's most famous love interest and Batman 3 seems like the perfect opportunity to introduce the character - given that Batman is now considered an enemy of the law himself, after the events of The Dark Knight.
Talia al Ghul is a lesser known character, to those outside the comic book community; though's she too has been one of Bruce Wayne's most dangerous love interests. Talia was even the mother of Bruce's son, Damian, in the DC Comics Universe. Like Catwoman, she is generally portrayed as a physical match for Batman, having been trained in several forms of martial arts. While there was no mention of Ra's Al Ghul having a daughter in the final cut of Batman Begins, she is referenced in passing in the film's official novelization - so her appearance in Batman 3 is not entirely out of the question.
Michael Caine revealed recently that Batman 3 will likely begin production around next May, so we shouldn't have to wait too long to learn whether Catwoman, Talia al Ghul, The Riddler, or possibly all three of these villains will be appearing in Nolan's third Batman adventure.
Any one of these characters could make for an excellent opponent for the titular masked vigilante in his next outing - though having all three on-board would certainly raise concerns that the film will suffer from villain overload a la Spider-Man 3.
So - which of these dastardly types would you like to see appear in Batman 3?