Guardiola has suggested that other clubs in Europe also have potential problems.
"We believe that we are right and we are going to appeal.
"Don't talk too loud, Barcelona, don't talk too loud.
"Because everybody's involved sometimes in situations.
"But we're going to appeal and hopefully we can play again in the Champions League against Barcelona."
Most of the questions in Guardiola's press conference were about the UEFA ban, but the coach didn't want to keep talking about it.
"It's a sensitive issue to talk about the legal actions because I don't know it, I'm not a lawyer," he said.
"All we can do is win the games."