Copyrights in Europe generally end 70 years after an author’s death.
Until about a year ago, Anne Frank was listed as the sole author of the diary and her father, Otto Frank, was listed as editor. In 2014, the foundation who owns the copyright to the diary changed this and added Otto Frank as co-author. Because of this little trick they can now argue that not all authors of the work have been dead for 70 years (Otto Frank passed away in 1980).
“The longer they can claim copyright protection, the longer they can ask money for publication of the works,” said Stef van Gompel, a professor at the University of Amsterdam who specializes in copyright law.