Film producer Daniel Toscan du Plantier, one of the central figures in the French film industry and the "best ambassador" for French film around the world, has died.

The producer of a string of European classics and organiser of the Cesar awards - the French equivalent of the Oscars - Toscan du Plantier's death has prompted tributes from the country's prime minister and film stars.

Flags were lowered to half-mast at the Berlin Film Festival

Aged 61, he suffered a heart attack at the Berlin Film Festival on Tuesday.

He was also known for being the widower of one of Ireland's most infamous murder victims, Sophie Toscan du Plantier, who was beaten to death in 1996 and whose killer has never been caught.

Toscan du Plantier headed French production company Gaumont in the 1970s and 80s.

He oversaw the production of classics such as Ingmar Bergman's Fanny and Alexander, Federico Fellini's City of Women and Francois Truffaut's The Last Metro.

He is somebody who I profoundly loved and is irreplaceable Jeanne Moreau Actress

He then became head of Unifrance, which promotes French cinema around the world.

French Prime Minister Jean-Pierre Raffarin said: "His death is a loss for cinema and culture."

"This tireless worker had put all his energy into the promotion and development of French cinema."

Actress Jeanne Moreau paid tribute to him as "somebody who I profoundly loved and is irreplaceable".

Veteran actor Pierre Arditi said he was a "great ambassador of French cinema".

"He was a little like the producers from 30 or 40 years ago, who made movies because they wanted to have a kind of love adventure with the films," he told France Info radio.

"They produced out of desire. They weren't doing it for business."

Antoine de Clermont-Tonnerre, president of the Chamber of French Film Producers and Exporters, said French cinema had lost its "best ambassador".

"His extraordinary personality, his irresistible humour and his panache make him a legendary character in the history of French cinema," he said.

Unsolved murder

Among Toscan du Plantier's last film projects were big-screen versions of operas Madame Butterfly and Tosca.

In 2002, Irish police reopened the case of the murder of his wife Sophie, who died on a remote country road near her holiday home two days before Christmas 1996.

Toscan du Plantier once claimed that police treated him with suspicion and kept him in the dark, saying the case would have been solved if it had happened in France.

But in 2000, he said he believed the Irish investigation would end with "a just solution".

He married Melita Nikolic in 1998 and had a total of five children from three marriages.