The 30-year-old midfielder claimed on Tuesday that the two clubs have already reached an agreement and that he was going to remain at the French club when his season-long loan deal from QPR ran out at the end of the season.
"We wouldn't be against the idea of keeping Joey Barton at OM, but we're not at all in a position to set the tempo," Labrune told 20 Minutes.
"He belongs to QPR. He's a player who's on loan without a buy-out clause, so we absolutely don't have any say in the matter. There is, in any case, no such deal as Joey Barton has suggested."
Barton's current contract with QPR runs until June 2015.