Questions in Poland after Macron hands Pope book with Polish stamp (Notes from Poland)

During a recent audience with Pope Francis, French President Emmanuel Macron gave the Pope a 1795 book by Immanuel Kant.

A photograph of the book shows that the book bears a library stamp from Lviv (now in Ukraine, but once part of Poland), leading the Polish foreign ministry to investigate whether the book was looted by Nazi forces during World War II.