Hundreds of Palace fans marched on Selhurst Park after UEFA ruled the Eagles could not compete in the Europa League and instead were demoted to the Europa Conference League.
The decision was made due to shareholder John Textor also owning fellow Europa League qualifiers Lyon.
Textor has agreed to sell his stake to fellow American Woody Johnson, but the deal is yet to be signed off.
An injustice
Nottingham Forest, who finished seventh in the Premier League last season, are set to replace Palace in the Europa League.
Nick Philpot from the Red and Blue Review podcast declared at the protest: "At the end of the day it's an injustice, just by a couple of admin errors. We qualified for it.
"We won the Cup - it should be we go into it without any question about it.
"You're penalising the entire club and the fanbase. Why would you do that?"