Lyon are taking legal action after Springbok lock Franco Mostert moved to Japan despite having a two-year deal with them.
The Top 14 outfit revealed the news via a press statement on their official website on Monday.
“Lyon Rugby notes with horror that Franco Mostert is in Japan and is training with the Ricoh Black Rams while he has committed to two years with our club,” read the statement.
Lyon announced Mostert’s arrival, from the Golden Lions, on March 16, along with eleven other new players.
“Faced with this serious violation of contract, law and basic values of rugby which are that a commitment be respected, the club will take all the necessary measures to see justice is done and today is approaching the competent legal and rugby authorities,” said the club.
Mostert has represented the Springboks in four Tests after making his international debut against Ireland in Johannesburg in June.