Barton has been linked with a loan move to France, but after Labrune revealed that QPR had cooled their interest in Marseille's Stephane Mbia, he admitted that it was now "unthinkable" that Barton would be joining the Ligue 1 club.
Labrune told French radio station RMC: "The condition was that we had a firm offer for Mbia.
"Having Barton on loan was something that we never thought of. Can you imagine that? At the time, I said, why not?
"However, the likelihood of QPR signing Mbia is now very low, and, in this case, the loan of Barton is unthinkable."
Barton is suspended from QPR's opening 12 matches of the season through suspension.