Everton have been sanctioned after breaching the FA's football agent regulations.
Andy Niedzwiecki, the agent who was representing Lascelles at the time, has been fined £10,000 and warned as to his conduct, and the player himself has been given a severe warning, the FA said on its website.
Lascelles, a ball-playing centre-back, is now 20 and at the time of the approach was under a scholarship agreement at Forest. He is still at the club, but this month has been linked with moves to Arsenal, Liverpool, Newcastle and Tottenham.
The FA said in a statement: "Everton have been fined £45,000 and warned as to their future conduct after breaching the FA's football agent regulations.
"The breach relates to the club's unauthorised approach to Jamaal Lascelles whilst the player was under a scholarship agreement at Nottingham Forest FC in the latter part of 2010.
"Andy Niedzwiecki, the football agent who was representing Mr Lascelles at the time, has been fined £10,000 and warned as to his future conduct after admitting his part in the matter.
"Jamaal Lascelles, who also admitted his part in the affair, has been severely warned as to his future conduct.
"The time-frame for any appeal has passed."