The 19-year-old runway beauty donned a stunning low-cut silky red dress, with a daring thigh high slit, for the "La Fille Inconnue" (The Unknown Girl) premiere, and happily posed for the cameras as she bared her left leg.
She clutched the front of her skirt to avoid tripping as she made her way up the steps at the Palais des Festivals venue, but in doing so, she suffered a wardrobe malfunction.
Bella didn't appear to notice the fashion faux pas, and continued to climb her way to the theatre.