Velvet Revolver members Slash and Scott Weiland could be fined for smoking onstage.
The band members both lit up during the concert at the International Arena in Cardiff on Thursday (June 7).
Slash and Weiland reportedly chain-smoked their way through the show, despite a ban on smoking in any enclosed space that was passed by the Welsh legislature in April.
The two musicians could each face a fine of £50, while the venue itself could be fined up to £2,500 for not stopping the artists from lighting up.
The Cardiff city council confirmed it would investigate the matter, reports iCWales.