What was the name of world war 2 movie about stolen art?

You're likely thinking of "The Monuments Men" (2014), directed by and starring George Clooney.

This film tells the story of a group of art historians and museum curators tasked with recovering stolen artwork from Nazi hands during World War II.

There are other war movies that involve art, but "The Monuments Men" is the most famous one focusing on the recovery of stolen artwork.