Clermont second row Sitaleki Timani received a straight red card for striking a Castres player in the face during Sunday’s Top 14 game.
Timani was retaliating to Castres replacement Rory Kockott after he antagonised him while celebrating a try.
Timani, 33, made 18 appearances for the Wallabies between 2011-13 and joined the French side in 2016.
The Australian lock was sent off in the 49th minute while Kockott was sent to the sin bin for being the cause of the offence.
The game finished 39-22 to Clermont and full match highlights are available below but may only be available to European viewers.