The titles of songs, books and movies, by themselves are not protectable by copyright which is why you can find such titles used over and over by various persons. However, depending on the uses made of the title as other than the title of the movie which enable it to become identified by the public as identifying the source/sponsor of goods or services (e.g., Star Wars), then it can be protected as a trademark. Based on the limited amount of information you have provided, it does not seem likely that you have anything to worry about, but more information about the usage of the documentary title is needed to be sure.
Answered on May 07th, 2014 at 3:36 PM