A junior futures trader such as Kerviel "could in no case do what he did without being seen" by his superiors, Philippe Hoube said after the verdict. "If justice had played its role, they wouldn't have sentenced him so heavily," he said.
An internal report by the bank has said managers failed to follow up on 74 different alarms about Kerviel's activities.
By the time his trades were discovered in early 2008, when banks were sliding into a global crisis, he had amassed losses of almost 5 billion euros on those bets in one of the biggest trade frauds in history.
The sentence -- a five-year prison term, with two years suspended, plus the payback of all the losses he incurred -- shocked many in the French public. After a global financial crisis that many blamed on big banks, many still believe Kerviel's claim that he was a victim of an unjust system.
"I'm someone who believed in French justice. But one day I understood that there is justice for the powerful and another for ordinary citizens," said Jean Debrex, a retiree who attended Wednesday's audience.
A few of the bank's executives resigned in the scandal's aftermath, including longtime Chairman Daniel Bouton. Kerviel's superiors were questioned in the probe, but none of them faced charges.
The bank says Kerviel made bets on futures contracts on three European equity indices. It said at the time that his net position appeared unremarkable because he balanced his real trades with fictitious transactions.
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