CANNES - US film giant Francis Ford Coppola returned to Cannes Thursday with the world premiere of "Tetro", a moody tale of sibling rivalry shot in Buenos Aires, and his most personal film yet.

Coppola's black-and-white indie movie kicked off the Directors' Fortnight, a talent-scouting sidebar to the main Riviera festival, after it failed to secure a slot in the main festival competition.

But critics and festival-goers queued round the block to squeeze into the screening, and welcomed the 70-year-old director with a torrent of applause as he arrived for a question and answer session after the show.

"Tetro" is Coppola's first original screenplay since 1974's "The Conversation" and the Oscar-winner says he drew on childhood memories to create a "personal" work about family bonds, but denies it is autobiographical.

"Nothing in the story really happened -- but everything is true," he quipped when asked to spell out the links between the movie, which stars Vincent Gallo in the title role, and the story of the Coppola clan.

"Tetro" is the tale of a 17-year-old Italian-American who travels from New York to Buenos Aires to search for his missing brother, who cut ties with his family, and his calling as a writer, a decade ago.

Shot last year in the Italian quarter of Buenos Aires, La Boca, it focuses on the two sons of a tyrannical conductor, inspired in part by Coppola's own musician father and uncle.

"When I made 'The Godfather', I didn't know anything about gangsters -- I had never met a gangster," Coppola said.

"But I knew they were Italian-Americans so I just made them like my family, in terms of how they ate and talked," explained the director, flanked by his wife Eleanor, his son Roman and two of his actors -- 19-year-old US newcomer Alden Ehrenreich and Spain's Maribel Verdu, with Gallo set to fly in later.

"In this case, although my family are not Argentinian-Italians... I thought this would be an opportunity to transplant some things from my family to Argentina."

But the parallels linking Coppola's gangland saga and his latest film end there.

"The difference between 'The Godfather' and this film, is four stabbings, two strangulations, 20 murders by gun, three murders by car accident, and one machine gun murder," the director deadpanned.

Coppola returned to the silver screen in 2007 after a 10-year absence, with the philosophical movie "Youth Without Youth," and the 15-million-dollar film "Tetro" is his third project as a writer-director.

"Throughout my career, whenever I made a film I always put on the title: Mario Puzo's 'The Godfather', or Bram Stoker's 'Dracula' -- because I always hoped one day I could have a film that was Francis Coppola's.

"To do that though I had to write the story and the script, because I had no right to say it was mine if someone else had written it -- because writing is the most difficult part."

A two-time Palme d'Or-winner at Cannes, Coppola was invited to screen "Tetro" at the Fortnight after failing to be selected to compete in the main festival, which runs until May 24.

Asked about the upset, Coppola confirmed he turned down an out-of-competition gala screening at the festival -- saying he felt more comfortable taking his film to the Fortnight.

"I said, if I can't come in competition I kind of don't want to be at a gala with a red carpet."

"This is more in the sprit of an independent film and it doesn't feel comfortable dressing in a tuxedo and going up the red carpet. I think here is more appropriate for this type of film."

"Tetro" is the first of two dozen films in the Director's Fortnight, which was launched in 1968 by avant-garde directors including Francois Truffaut, and puts its focus on discovering new talent.

It can boast of having helped launch the careers of high-flyers such as Stephen Frears, Nagisa Oshima, Martin Scorsese and Wim Wenders.