FILE PHOTO - The Facebook logo is shown at Facebook headquarters in Palo Alto, California, U.S. May 26, 2010. REUTERS/Robert Galbraith/File Photo

BERLIN (Reuters) - Germany's justice minister has asked Facebook FB.O Chief Executive in a letter to be transparent with users by giving them more control, saying allegations of the improper use of data for millions of people is unacceptable, a German media group reported on Thursday.

Media group RND said in her letter, Katarina Barley also called on Facebook to strictly implement privacy by default settings and to set up an internal mechanism to protect users from misuse by third parties like Cambridge Analytica.