Cotillard played Leonardo DiCaprio's quixotic wife in Nolan's last film, the dream-within-a-dream-within-a-movie Inception, which also starred Hardy and Gordon-Levitt. The lovely French actress is currently pregnant and due and the spring, while The Dark Knight Rises is set to begin principal photography in May. According to Le Figaro, she'll be limiting herself to one film this year, and has decided that Nolan's final Bat-picture will be that film.
Right now, the discussions center around scheduling, and the tentative plan is to have Cotillard begin in London this June, shooting through summer in locations including Pittsburgh and Los Angeles, and then finish up in New York at some point in November. This gives some insight the global scale of the production, which is also said to include Detroit and India as filiming locations.
Since Bruce Wayne's previous love interest, played by both Katie Holmes and Maggie Gyllenhaal, was basically vaporized in The Dark Knight, Nolan has been on the prowl for an actress to play a romantic foil for Batman, and he reportedly also met with Kate Winslet, Naomi Watts, and Rachel Weisz regarding the mysterious role. The current assumption is that this love interest will be a squeaky clean counterpoint to Hathaway's Selina Kyle, who moonlights as Catwoman.
While some past Batmen have been charming and seemingly squared away, Bale's Bruce Wayne seems sort of like damaged goods, to put it lightly. Can Cotillard play a woman who wouldn't be freaked out by a billionaire who dresses up as a bat and beats the hell out of people?