Movie review: Shedding light on the other musician in ‘Mozart’s Sister’

French filmmaker René Féret’s mutedly effective 18th century-set drama “Mozart’s Sister� takes a historical truism that the legendary composer’s five-years-older sister Maria Anna, or “Nannerl,� was a musical prodigy in her own right before the glare of baby brother’s genius and gender mores cut short her ambition — and imagines the circumstances surrounding her retreat from the limelight.

While on a royal court tour of Europe, 14-year-old Nannerl (subdued beauty Marie Féret, the director’s daughter) dutifully accompanies young Wolfy on harpsichord, but chafes at being left out of papa Mozart’s composition lessons, or being forbidden to play her beloved violin anymore. (Unladylike, apparently.)

Only newly sparked friendships with Louis XV’s abbey-cloistered daughter and, separately, his eccentrically mannered widower son the Dauphin, give Nannerl a taste of an unheard-of world in which her charms and talents might be fostered independently.

Far from grand costume drama or a modernist jab, Féret trades in slice-of-life realities (the Mozart family’s itinerant existence, court eccentricities) and character nuance, keeping Féret’s observant, quietly radiant turn a sort of bittersweet, unfulfilled anchor.

The object isn’t to stir you into what-if feminist outrage so much as to let a culturally magnificent era’s societal inequalities act as a dissonant countermelody to a famous artist’s biography.

“Mozart’s Sister.� No MPAA rating. Running time: 2 hours. At selected theaters.