Celtic have been fined €23,000 (£20,615) after an "illicit banner" was displayed during last week's Champions League qualifying win over Linfield.
The Uefa punishment also includes a penalty for "blocked stairways", but a "kit infringement" charge was dropped.
Uefa rules prohibit "any messages of a political, ideological, religious, offensive or provocative nature".
This is Celtic's 11th punishment in six years relating to misconduct from supporters during European ties.
Following the initial charge, Celtic condemned the conduct of "a small minority of the crowd", adding: "Any support for a paramilitary or proscribed terrorist organisation has no place at Celtic Park."
The Scottish champions then announced a two-game closure of the area of the stadium occupied by the Green Brigade fans' group.
That section of Celtic Park was empty when Brendan Rodgers' side drew 0-0 with Norwegian side Rosenborg in Wednesday's Champions League third qualifying round first leg.