Monaco have accused some of Europe's top clubs of making illegal approaches for teenage striker Kylian Mbappe.
The Ligue 1 club said in a statement that "important European clubs" have made contact with the 18-year-old France forward without permission.
Monaco may ask world governing body Fifa and the French league to consider disciplinary action but Fifa say they are yet to receive a complaint.
BBC Sport understands Manchester City are the only English club accused.
They have refused to comment officially however a City source told BBC Sport the two clubs developed a positive relationship over their two Champions League meetings last season.
It is understood negotiations over the sale of Bernardo Silva to City for £43m earlier in the summer were positive, and the ongoing dialogue over £50m-rated full-back Benjamin Mendy has also been cordial.
The source added they did not believe City had conducted themselves in such a way that would breach the trust that exists between the two clubs.
Arsenal have also been strongly linked with Mbappe, and Monaco reportedly rejected an £87m bid for the France international in June.
Monaco claim clubs have breached regulations of both Fifa and the Ligue de Football Professionnel.
Fifa rules state: "A club intending to conclude a contract with a professional must inform the player's current club in writing before entering into negotiations with him."