Ibrahimovic got involved in a heated discussion with the Danish defender during Thursday's game in Istanbul and pictures appeared to show him grabbing his opponent by the throat.
Referee Milorad Mazic did not take any action at the time, but it is understood the incident was seen by the fourth official, who determined no sanction was necessary.
The matter will therefore not be subject to review by European governing body UEFA, and no retrospective action can take place.
Fenerbahce manager Dick Advocaat also played down the incident after the game.
"That is part of football," he said
"I don't talk about individuals."
Ibrahimovic, who has not scored in his last six games, had been an early replacement for the injured Paul Pogba.
United were beaten 2-1 to slip to third in Group A.
Source : PA
Source: PA