The French frontman has scored five goals in as many games since agreeing a season-long loan switch at the St James' Park outfit.
Redknapp told West London Sport: "I don't know what the deal is. I don't know what the chairman Tony Fernandes or [chief executive] Philip Beard have agreed.
"I don't know whether there's a fee agreed or not. He's certainly playing well for them. I said last season that he's a 10 to 15-goal a season man."
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