The winger has been likened to Chelsea star Eden Hazard and is rated at €20 million.
Le 10 Sport says Manchester United, Arsenal, Manchester City, Tottenham, Liverpool, Southampton, Stoke City, Juventus, Inter Milan and Borussia Dortmund are all chasing the Moroccan's signature.
Antonetti told RMC: "Keep Sofiane? It is going to be difficult.
"We all know that in France, we must balance the budget at the end of the season. It is expected that Boufal will be transferred at the end of season. This is part of the DNA of Ligue 1.
"The best players, at some point, are drawn to the richest championships."
