In Societe Civile Succession Richard Guino v. Renoir, (9th Cir., December 2008), the court held that works first published in France no later than 1917 without a U.S.-style copyright notice were never subject to U.S. copyright under the 1909 Copyright Act, and therefore could not have fallen into the public domain in the U.S.
This holding is particularly interesting because, as the Ninth Circuit noted, "[t]he year 1923 is significant because the 1976 Act . . . and the 1998 Copyright Extension Act operate together to create a bright line rule for which works are now in the public domain: works published before January 1, 1923 are generally in the public domain." This rule is even noted in Copyright Office Circular 22 which states
. . . the U.S. copyright in any work published or copyrighted prior to January 1, 1923, has expired by operation of law, and the work has permanently fallen into the public domain in the United States. For example, on January 1, 1997, copyrights in works first published or copyrighted before January 1, 1922, have expired; on January 1, 1998, copyrights in works first published or copyrighted before January 1, 1923, have expired. Unless the copyright law is changed again, no works under protection on January 1, 1999, will fall into the public domain in the United States until January 1, 2019.