A devastating picture of a corrupt system out of control emerges from two documentaries on the financial crisis that coincide with Oliver Stone's return to a fictional Wall Street at the Cannes film festival.

"Inside Job", directed by Charles Ferguson and "Cleveland versus Wall Street", by Swiss-born director Jean-Stephane Bron, both provide a meticulous dissection of a disaster that brought the global banking system to its knees.

Stripping down a hugely complex series of events, the films distil a simple message from their examination of the speculative frenzy that linked suburban American home buyers, complacent officials and irresponsible global financiers.

"This was a bank robbery but it was a robbery committed by the president of the bank, not by some random guy who walks in with a gun," Ferguson told Reuters in an interview.

"This was a crime committed by people who ran the financial system," he said. "We let these people run amok and they crashed the system."

Wall Street's most illustrious names are now caught up in a public relations battle to save their reputations from the tide of popular wrath against the sector, which they say is often unfair and ill-informed.

But with Stone's old villain Gordon Gekko also stalking the Croisette in "Wall Street: Money Never Sleeps", the growing mood of public anger has clearly spread to the world's biggest film festival.

"I think the bankers should be in jail, but it doesn't happen that way, does it?" Stone told Reuters in an interview after his film was shown out of competition.

"It's out there and people know ... that the banks are screwing us and they are, and they got away with it."

INTERVIEWS

The two documentaries are the cinema equivalents of the wave of books on the financial meltdown that have filled best-seller lists in recent months as the public has searched for explanations for what went wrong.

Ferguson's film focuses on explaining the banking crisis while Bron uses the format of a trial movie to show the struggling victims of the subprime mortgage collapse who lost their homes when the financial winds changed.

"Everybody knows the word 'subprime', but we don't know exactly what it means, what is behind this word," he said. "You need characters, that's why we did it as a trial."

Ferguson, whose previous films include the Iraq war documentary "No End in Sight", interviews a host of big names from the head of the International Monetary Fund, Dominique Strauss-Kahn to billionaire investor George Soros.

A jaunty soundtrack and crisp narration by Matt Damon lay out the detail of a story that begins with reckless bankers in Iceland and moves across the globe, taking in subprime mortgages, collateralized debt obligations and credit default swaps as it goes.

"We thought, what is the essential thing here? Let's take away the inessential things, show only the essentials and do that as cleanly as possible," Ferguson said.

Both filmmakers agree with a global push toward tighter regulation of the financial system, in part to protect markets against themselves. But they say the crisis also reveals a wider problem with society as a whole.

"Of course we need more rules and regulation. That's even obvious for people on Wall Street," Bron said. "But really, there is a lack of democracy, that's the main point."