StudioCanal is developing a World War II movie about U.S. and German soldiers teaming up for a rescue of French prisoners near the end of the war in the Austrian Alps.

The French company has acquired movie rights to Stephen Harding’s “The Last Battle: When U.S. and German Soldiers Joined Forces In The Waning Hours Of World War II In Europe.” The Picture Company’s Andrew Rona and Alex Heineman will produce with Bryce Zabel, who adapted the book.

Harding’s book, published in 2013 by Da Capo Press, describes a mixed force of U.S. Army, German Wehrmacht and Austrian resistance fighters acting together to prevent the recapture of 14 French prisoners being held at Itter Castle. An SS assault party had been ordered to retake the prison shortly after Adolf Hitler’s suicide in April, 1945.

The prisoners included two former French Prime Ministers, two former commanders of the French military,...