David Lister: The best performances at Cannes are at the press conferences

In previous visits to the Cannes Film Festival I have been as entertained by the daily press conferences as by the films. Film writers from across the world manage to put on a display of sycophancy like you have never seen.

The rush to the platform for autographs by the world's film press is so frantic as to make any baying crowd at a Leicester Square premiere look downright sedate. And then there are the "questions". My favourite moment was when a film writer from Lebanon asked Charlton Heston the "question": "Mr Heston, are you aware that you are my father, my mother, my sister and my brother?"

But I also enjoyed a reported exchange at the current festival when a film writer said to Lynne Ramsay, director of We Need To Talk About Kevin, that the film about the boy serial killer was a particular "horror" for him as he had just become a father. Don't worry too much. Your little treasure is not likely to become a serial killer. Just pray he doesn't become a film critic.

Or, of course, a film director. Lars von Trier took the Cannes press conference to a new level this week, declaring on Wednesday morning that he understood and had sympathy with Hitler, then declaring that afternoon that he was not a Nazi, and then being banned by the authorities from coming within 100 metres of the main festival venue.

Those of us who have suffered under the French bureaucracy at Cannes will appreciate the exactness of those 100 metres. I once turned up without the correct accreditation and had literally to stand in the corner for several hours as punishment before I was given the formal telling-off and new accreditation. It ain't all glamour out there.

One inside these press-conference love-fests there are unwritten rules, the main one being that you never but never say anything remotely critical. When a couple of us did one year, at a British film to boot, we were bawled at by the movie world's pre-eminent bawler, producer Harvey Weinstein, who told us with a largesse of decibels that it was our job to support our film industry.

Directors know how to exploit the unwritten rules too. The biggest unwritten rule is publicity above all. The film world is rather brilliant at this. (Why don't other art forms have daily press conferences at their festivals? Why never a Barenboim, Rattle, Lang Lang press conference at the Proms?) Von Trier found one way of getting publicity for his film, though it arguably backfired. The Terrence Malik way at this year's festival was even better – not turning up at all. The mystery of the enigmatic absentee is always a winner. Add to that the fact that the stars of your film will spend the whole time singing your praises, which helps when the star is Brad Pitt.

Pitt also explained Malik's absence quite poetically, saying: "It is odd for an artist to sculpt something and then be a salesman." Go tell that to all the other sculptors-turned-salesmen, Brad.

When opera and politics share a stage

Placido Domingo made a farewell of sorts at the Los Angeles Opera where he has been general director for 15 years. Though the 70-year-old will stay there until 2013, he has given his last scheduled singing performance for the company playing Oreste in Iphigenie en Tauride. The gala evening was quite an occasion, and was attended by the American Vice-President Joe Biden.

Managing to make a clumsy and utterly unnecessary link between Domingo's farewell and the killing by US commandos of Osama bin Laden, Mr Biden said of the commandos: "Placido Domingo is probably the only man who could appropriately sing their praises."

It was an excellent demonstration of why politicians should keep quiet when they attend the opera.

Blessed are the glamrockers

Lady Gaga has a new album. But who should get the credit for it? Is it the lady herself, or her two demi-gods Elton John and David Bowie? In this instance demi-god is not an over-statement, as Lady Gaga has revealed that she used to pray to the two rock stars when she was a mere Girl Gaga.

At school she was bullied, she said in an interview, recalling: "I got profanities written all over my locker. I got pinched in the hallways and called a slut." (And you thought they had it tough on Glee.)

The bullying apparently resulted in her praying at home in her bedroom to her two personal deities Elton John and David Bowie for the creativity to do something great. And, praise be to the two gods, the album is out on Monday. I hope they get a share of the royalties.