The story was originally run on BBC Swahili website but was not published in English, although it was reproduced by many news outlets, including Nigerian and British newspapers.
The police in Anambra state, where the restaurant was purportedly located, denied the story when it appeared in a Nigerian newspaper a week ago.
In a retraction published on its website, the BBC wrote: “The story about the Nigerian restaurant which we published here was a mistake and we apologise. It was incorrect and published without the proper BBC checks. We have removed the story and have launched an urgent investigation into how this happened.
“The BBC Swahili service’s reputation for accuracy and balance remains of paramount importance to us and we are taking the appropriate steps to insure that mistakes like this do not happen again.”