The French banking regulator on Friday fined Société Générale €4m ($6.3m) for “serious failings” in the bank’s internal control procedures exposed by a rogue trading affair in January.

The penalty is the biggest imposed by the Banking Commission for breaches of its risk control regulations and reflects the scale of systemic and managerial short-comings identified by its investigators since SocGen revealed a €4.9bn loss from unauthorised trades.