"Okay, room. Haiti is watching us tonight like you cannot believe," Penn told the black-tie crowd who had paid up to $100,000 for a table at the "Carnival in Cannes", just steps from the famous red carpet.

Three people paid $100,000 each in an auction to accompany Penn on a three-day trip to Haiti where the actor, a two-time Academy Award winner, has been active since the country's devastating 2010 earthquake.

In an expletive-laden yet impassioned speech, Penn exhorted guests to give generously and not turn their backs on Haiti. Celebrities included members of the Cannes jury - actors Ewan McGregor and Diane Kruger and designer Jean Paul Gaultier.

Ben Stiller and Chris Rock, voice stars of animation blockbuster "Madagascar 3" also attended, and designer Giorgio Armani, an event sponsor, made an appearance at the event co-hosted by model Petra Nemcova and "Crash" director and screenwriter Paul Haggis.

President of the Cannes jury four years ago, Penn was named "Ambassador at Large for Haiti" by new President Michel Martelly this year. In the days following the earthquake, Penn started the J/P Haitian Relief Organization with a goal of getting displaced people back into permanent homes.

"There's this very tangible success story that Haiti can be that could be a domino effect throughout the world," Penn told a news conference on Friday.

It was only the third time in its 65-year history that Cannes has lent its name to a fundraising cause, but this time the gala for Haitian relief was not tied to any festival film. In the 1980s it helped raise funds for the Pasteur Institute and in the 1990s for a Venice opera house destroyed by fire.

Penn said the event came together after Thierry Fremaux, the festival's general delegate, "called and asked how he could help".

Rebuilding Haiti will depend on private funding and collaboration between donors, Penn said, citing the non-profit groups of Nemcova and Haggis - the Happy Hearts Fund and Artists for Peace and Justice - both of which have focused on schools.

WINNING BID

Penn lashed out at the media, however, for parachuting into Haiti but then not following through to keep reporting on the zone during its rebuilding.

"It's not only celebrities that just went for the day. It's the whole ... world. It's the entire media. It's all of you," he told the press. "The reason people get Haiti fatigue is because they never committed in the first place."

Singer Lyle Lovett gave a short concert before Haitian band RAM performed and waved the country's blue and red colors on what was Haitian Flag Day.

Martelly, elected president in 2011, appeared on pre-recorded video from Port au Prince, playing the piano, singing and calling Penn "a friend and an inspiration for our country."

Haggis, who took his first trip to Haiti two years before the quake, tried to incite higher bidding on the auction items, announcing a "Golden Globes Weekend" package would also include a date with the Scottish actor Gerard Butler, whom he pulled up on to the stage, to the actor's embarrassment.

A man suddenly leapt up, yelling: "100,000 euros without Gerard Butler!" to seize the winning bid.

Speaking at the news conference, Haggis said the world had largely washed its hands of Haiti throughout its troubled history.

"Honestly, until the quake, no one really gave a damn about Haiti," said Haggis, adding: "Like Sean said, 'Give these people a shot that they've never had'."

(Editing by Sophie Hares)

• A Permanent Economic Emergency