Gueye announced over the weekend that he wanted to end the Bosman arrangement.
But France Football's Nabil Djellit reports a penalty clause exists should the midfielder wish to get out of the deal.
He posted online: "Pape Gueye has a clause in his contract of €5 million which he must pay in the event of a breach.
"It is his price in order to avoid any complications. He can also win legal proceedings over time."
Djellit added that "Angers and Marseille" are keen on signing the midfielder.