The €4.9bn fine levied against ex-Société Générale trader Jérôme Kerviel this week is a first for France, but the financial sentence, which technically could see the bank request seizure of his assets - is likely never to be enforced.

The heavy financial penalty, handed down after Kerviel was found guilty of abuse of trust, forgery, use of forged documents and computer abuse - is the highest ever levied in France. Up to now, the highest amount of damages granted was €630m against Thales in compensation for a dispute over a warship sale in 1991 to Taiwan.