Also, can you supply a screenshot showing exactly what the problem looks like please? ("appears after every para return" seems to imply that the hash character appears at the start of the next paragraph. I.e. Anything after a "new line" or "new paragraph" character should be on the next line/paragraph.)
I've tried all kinds of things to re-create this but there's nothing I do that will show a hash character (except, of course, either typing a hash character, adding it from the enhanced character palette, or inserting a page number).
Other useful information for you to give would be:
* The OS you're using.
* The version of Scribus you're using (the text copied from the "About Scribus" dialog will help).
* What font you're using.
* Have you tried "cleaning" the text by putting it through a plain text editor before putting it into Scribus?
* Do you get the same result in copy/paste as you do by using "Get Text" or "Edit Text"? (Where are you pasting the text in? In the Story Editor or straight onto the page?)