Jerome Kerviel, the “rogue trader” who cost French bank Societe Generale almost five billion euros in losses, has won a wrongful dismissal case.

An industrial tribunal – made up of representatives of employers and trade unions – has ordered the bank to pay him 450,000 euros in compensation.

The reason they believed he was fired without “real and serious cause” is because the bank waited too long to get rid of him after becoming aware of his misconduct.

Societe Generale called that “incomprehensible” and plans to appeal against the ruling.

Kerviel spent five months in prison after being found guilty of breach of trust and fraud for unauthorised trades in 2008, which he says his former employer knew about.

The ruling comes as Kerviel faces a separate civil case, due to start next week, over how much he has to pay the bank towards the losses.

EUR4.9bn SocGen rogue trader wins unfair dismissal case – Jerome Kerviel, the rogue trader who was jailed in 20… https://t.co/n96QaYJGb4— Dominic Higgins (@dominichiggins) June 7, 2016