The Golden Lions Rugby Union is adamant lock Franco Mostert has no case to answer in his ongoing contractual saga with French side Lyon.

Lyon threatened to take legal action against Mostert for breach of contract after the player joined the Ricoh Black Rams instead of reporting for duty at the French club after the completion of the Rugby Championship.

The Lions, however, hit back with claims that Lyon didn't follow the correct procedures when they initially signed Mostert, therefore the two-year contract between the player and club is null and void.

'We are aware of Lyon's statement regarding their decision to sue Franco, but it is something we don't take seriously,' Lions high-performance manager Bart Schoeman told Netwerk24.

A supposed agreement between Lyon and the player was reached in December 2015, with the club officially unveiling him in March 2016. Legally Mostert was still bound to the Lions in both instances.

'Lyon operated outside World Rugby's regulations, which states a club can't sign a contract with a player while he is still under contract with another team. According to these regulations, the club [in this case Lyon] had to negotiate with Mostert's employers [the Lions] and not directly with the player or his agent.

'If Lyon had send us a copy of the contract, we could at least have discussed the situation. But we haven't seen any documentation,' said Schoeman. 'If there is a contract it is illegal, because the GLRU was not involved in the process.'

Mostert has since signed a contract extension with the Lions until the end of 2018 and has been loaned out to the Ricoh Blacks Rams.

'Franco followed the same route as Warren Whiteley, Jaco Kriel, Lionel Mapoe and Elton Jantjies. For the next two years, they will play in Japan during the off-season before returning home for Super Rugby,' Schoeman added.

Photo: Johan Rynners/Gallo Images