About 100 Palestinian flags were held up by supporters at Celtic Park before the UEFA Champions League play-off first-leg tie against Israeli club, Hapoel Be'er Sheva last Thursday morning (AEST).
As UEFA prohibits "gestures, words, objects or any other means to transmit any message that is not fit for a sports event, particularly messages that are of a political, ideological, religious, offensive or provocative nature", the governing body confirmed that Celtic had breached Article 16 (2) of their disciplinary regulations.
The Green Brigade, Celtic's Ultra fans, have said that in response to UEFA's "petty and politically partisan act" they are "determined to make a positive contribution to the game and (launched) a campaign to #matchthefineforpalestine."
"We aim to raise £75,000 which will be split equally between Medical Aid Palestine (MAP) and the Lajee Centre, a Palestinian cultural centre in Aida Refugee Camp on the outskirts of Bethlehem."
As at today, their appeal on the Go Fund Me website passed the £120,000 ($208,000) mark, far exceeding their target of £75,000 ($130,000).
If found guilty of a breach, this will be Celtic's ninth UEFA punishment for fan misbehaviour in the past five years - a record that has racked up £100,000 ($172,000) in total.
Celtic were fined over £15,000 ($26,000) for the same offense, Palestinian flags being waved at a Champions League qualifier against KR Reykjavik, in July 2014.
The current case will be dealt with by UEFA's Control, Ethics and Disciplinary Body on 22 September.