The game, won 1-0 by the Scottish champion, was originally due to be played behind closed doors after the racist abuse of Monaco midfielder Aurelien Tchouameni in August but around 10,000 school children and accompanying adults were allowed to attend.
The contest was marred by the booing of Rangers' black players, with Glen Kamara seemingly subjected to particularly vocal taunts.
Last March, UEFA ruled Kamara had been the victim of a racist slur from Ondrej Kudela in Rangers' fixture against Sparta's Czech rival Slavia Prague.
However, after an investigation by a UEFA Ethics and Disciplinary Inspector, European football's governing body said no further action would be taken.
A statement confirmed: "In accordance with Article 31(4) of the UEFA Disciplinary Regulations, a UEFA Ethics and Disciplinary Inspector was appointed to conduct a disciplinary investigation regarding potential discriminatory incidents which allegedly occurred during the 2021-22 UEFA Europa League group stage match between AC Sparta Prague and Rangers FC played on September 30, 2021.
"The investigation has now concluded that there was insufficient evidence of racism or discriminatory conduct at the match to warrant the opening of disciplinary proceedings against AC Sparta Prague."
After the game, Sparta issued a statement to insist any allegations of racism were unfounded.
"It is absolutely unbelievable that after a match we have to watch innocent children being attacked and face unfounded accusations of racism," the statement read.
"You are describing the behaviour of children incorrectly, arrogating to yourself the right to judge the expression of emotions of six-year-old children who have no idea what racism is. It's an impertinence."