A staggering number of paintings were once thought to be Rembrandts, but of the 800 or so works attributed to the Dutch master during the 19th century, only about 300 remain authenticated. Interestingly, the 1800s were also a period in which France dominated Rembrandt collecting and research. In the 20th century, expertise shifted to Holland, Great Britain, and the U.S., leaving French holdings isolated and neglected for a time. The Louvre, however,...