Barcelona risk further punishment from UEFA after allowing 30,000 pro-independence flags to be waved by supporters before their Champions League game against Celtic at Camp Nou on Tuesday.
The flags, known as esteladas, were handed out by pro-independence groups before the game and have previously seen the Catalan club fined by European football's governing body on two occasions.
They were hit for €30,000 last July after fans waved the flags during the 2015 Champions League final win over Juventus in Berlin.
And a €40,000 fine followed last October when the flags were brought to a Champions League group game against Bayer Leverkusen.
Barca have taken the case to the Court of Arbitration for Sport and are currently awaiting a verdict.
Supporters brought the flags out before kick-off against Celtic, revealing them and jeering loudly when UEFA's Champions League anthem began to be played. That was followed by loud chants of "Independence."
The flags represent the separatist movement in Catalonia as sections of the region seek independence from Spain. Sunday -- Sept. 11 -- was the national day of Catalonia and thousands of people gathered to march through Barcelona.
UEFA say the esteladas are guilty of "transmitting messages of a political nature," and the Blaugrana have encountered problems domestically as well as in Europe.
Spanish police had originally banned them from being allowed at last season's Copa del Rey final between Barca and Sevilla, before Spanish courts overturned the prohibition.