She is the face of Gucci, and the spitting image of her mother, Princess Caroline of Monaco, when she was a young woman. And now Charlotte Casiraghi can add the toast of the Cannes film festival to her accolades. Charlotte appeared on the red carpet at the screening of Madagascar 3 on Monday and showed that she is swiftly developing a sensuous style all of her own. The beautiful brunette opted for a teal ruffled dress from Gucci. This was a far sexier style than our own Duchess of Cambridge would opt for. A plunging neckline that was softened by the ruffled pleated edges, with a bar back and then further…