There was no attack on Bono. Even the police refused to arrest the alleged attackers until they were forced to do so by the Socialist government. Bono himself initially said nothing had happened to him.
One of Bono's bodyguards broke the broomstick that someone was using to wave a Spanish flag. This person did not hit Bono, either with the flag or with the stump of the broomstick that was left. When the police examined the photos and arrested everyone around Bono, they had to let them go without charges, because there was no attack on Bono. (Personally, I think there should have been, because he was on our [American] continent negotiating with Chavez two days after this fictional "attack.")
Interesting that FR is now being trolled by Spanish leftists.