PARIS — Jim Sturgess will play the male lead opposite Kirsten Dunst in Juan Solanas’ $50 million “Upside Down,” a Romeo and Juliet-style sci-fi fantasy.

Pic is set up at Aton Soumache’s Onyx Films and produced by Soumache and Dimitri Rassam. Jim Skotchdopole (“Man on Fire”) will exec produce. Key techs includes “Watchmen” production designer Alex McDowell.

WB distributes in France and Tele Munchen Group will handle the German distrib. Gregoire Melin’s international sales shingle Kinology reps the film in other markets.

“Upside Down” is co-produced by Studio 37, a subsid of France Telecom-Orange, and Montreal-based company Transfilm.

Pic is in pre-production and will start shooting in Montreal in mid-February for a fall 2011 release.