Set in 1567 against a French civil war between Catholics and protestants, Bertrand Tavernier’s “La Princesse de Montpensier” is a beautifully shot romantic epic centering on on a heart-stoppingly beautiful young teenager (Melanie Thierry) who enters into an arranged marriage with a prince she hardly knows. She’s something of a feminist, torn between her duties to her husband and desire for a childhood friend (Gaspard Ulliel). Lambert Wilson is very good as the film’s moral center, a war-weary count assigned to tutor her for presentation at court — who of course falls for the princess himself.