It will help if you can get other people to do this as well because if more people report the problem Facebook will take this as additional proof. Don’t overdo this however – aim for another two or three people to submit reports.

1. Log in to Facebook
2. Go to the page you want to report as a duplicate page. I’m using the city of Brisbane as an example i.e. as if I were the admin of the official Brisbane City FB page and this was the duplicate

1. Click on the … menu and select Report Page

Select the Duplicate of another Place option

1. Start typing the name of the Facebook page this page is a duplicate of. Pages will appear as you type.
2. Select the page that this page is a duplicate of
3. Click on Submit

Now wait for the facebook admins (or robots) to process your request. This may take a while but keep an eye out for notifications or to see if the duplicate page is removed