Carr had followed the striker since his junior days at Metz.
He told The Journal: "I had actually known about Papiss for some time. I did a lot of work with Metz, who have a Senegalese Academy, would you believe, and Papiss was there.
"This was a few years ago and the problem then was him not being able to get a work visa; I think there was an issue with his passport.
"Then the next thing you know he appears at Freiburg, so we went for him in January.
"Freiburg wanted £15m, which was out of our price range, then they went down to £12m and eventually £9m and we was ours."