Supporters of Catalan independence are to protest at Barcelona's Champions League match with BATE Borisov on Wednesday in defiance of UEFA's stance on such matters.
Twice the Catalan club have been fined by UEFA for pro-independence displays by fans at the club's games.
Several organisations which support independence for the Catalan region from Spain are to distribute 30,000 pro-independence flags for fans to wave at the Nou Camp.
In June UEFA fined Barcelona 30,000 euros after fans displayed the estelada, a Catalan pro-independence starred flag, at the Champions League final.
When a similar display took place during Barcelona's Champions League match with Bayer Leverkusen in September UEFA imposed a fine of 40,000 euros on Barcelona last month.
A statement from the groups organising Wednesday's protest read: "On behalf of four organisations of Catalan civil society, namely the Platform for National Catalan Sports Teams (PPSEC), the Omnium Cultural association, the Catalan National Assembly (ANC) and Drets.cat, with a combined membership of over 100,000, we wish to express our total disagreement with this sanction, which constitutes a grave attack on freedom of expression and opinion.
"We wish to make it clear to UEFA that the Catalan supporters expressed themselves in an entirely peaceful manner.
"They were protesting in defence of civil rights and the right of Catalans to decide their future democratically.
"We are dismayed that a body such as UEFA cannot accept a situation whereby supporters express themselves in a sporting and respectful manner.
"As such, we wish to declare our solidarity with FC Barcelona and its supporters. We consider that it is not legitimate to restrict the freedom of expression of a set of supporters who see football matches as festive occasions and as a good opportunity to voice their demands.
"They do so through chants and symbols that are not violent and are not prohibited anywhere. Moreover, they are historically associated with Catalan sport and with protest rallies, especially over the last five years."