Black Cats manager Martin O'Neill confirmed that the defender is heading for Wearside in the hope of clinching a loan deal.
O'Neill said: "I'm hoping that he's making his way over at this minute.
"I'm not sure that anything has been absolutely and utterly completed, but it would be a loan until the end of the season.
"Of course, we have a number of positions we would like to try to fill between now and the end of January, and I'm hoping something might materialise.
"But there's a long bit of distance to go yet."
Mangane joined Saudi Arabian side Al Hilal from Rennes last summer, but now looks set to make the move to the Premier League.