The scene inside the ballroom of Vienna's Hofburg Palace could have been lifted straight from The Sound of Music: young women in swishing dirndl dresses linked hands under chandeliers with students in traditional loden suits as they gently waltzed to the rhythmic orchestral sound of Johann Strauss.
But outside the building last Friday, the spectacle was different. Phalanxes of white-helmeted Austrian riot police stood with shields and truncheons.
"Nazis Piss Off, Nobody Misses You!" read one of the banners held aloft by demonstrators. Ugly scuffles ensued.
The event they were so vociferously objecting to was a traditional Vienna student ball known as the "Korporierten-Fest". The student ball, started in 1952 as part of Vienna's ball season, has gained an unsavoury reputation for being a white-tie extravaganza for the elite of Europeans' political far right.
The scenes are bound to be an embarrassment to the Viennese ball tradition in general, considered a cultural treasure in Austria. There are more than 250 balls across the city from 31 December until early March. The most high profile is the Opera Ball, which has in the past been attended by everyone from the Duchess of York to Paris Hilton.
It is not the first embarrassment caused by Korporierten-Fest's far-right links. The United Nations cultural arm, Unesco , dropped the entire Viennese ball concept from its list of Austrian cultural traditions last month after protests from anti-fascist campaigners. Unesco said the student ball – which is the only one with such political connections – had failed to live up to its principles, which gave a "special priority to tolerance and respect for other cultures".
Its reputation was dutifully upheld last Friday. Hosted by Heinz-Christian Strache, leader of the far-right Freedom Party, guests included Marine Le Pen, the leader of France's National Front, and representatives from the Belgian far-right party Vlaams Belang. The Viennese ball might have escaped with Unesco's rap on the knuckles, had it not been for an initially unreported anti-Semitic tirade delivered from Strache's ballroom box to some 3,000 of his right-wing guests last Friday, describing Austria's far-right as the "New Jews".
By yesterday it had become the focus of a row about everyday anti-Semitism and the rise of popular right-wing Austrian nationalism. Referring to the protesters outside, Mr Strache told his audience they should not be prepared to have their "wonderful cultural party" ruined by protesters, whom he described as "anti-democratic perpetrators of violence". He then claimed the violence outside was like "Kristallnacht" – the 1938 Nazi pogrom that foreshadowed the Holocaust – and declared: "We are the new Jews!" Reports in the Austrian press subsequently revealed that Strache's Freedom Party aide, Klaus Nittmann, had referred to the yellow star the Nazi regime forced Jews to wear and said: "Organisations behind the ball end up getting a Jewish Star pinned on them."
And in what was seen by many as adding insult to injury, last Friday's Vienna student ball just happened to fall on Holocaust remembrance day.
Austria's Jewish community has been sufficiently outraged to demand that state prosecutors investigate Strache. The ruling People's Party described his words as a "slap in the face for all victims of the Nazis' criminal regime". Strache's Freedom Party dismissed the criticism as "artificial and ridiculous outrage", while Strache himself said he did not intend to "play down the agony forced upon the Jews".
Yet his outburst has raised disturbing questions about his party, which is now Austria's second political force. It made huge gains in recent Vienna city polls with a virulently Islamophobic campaign.
Strache is a member of one of the Austrian student clubs – "Burschenschaften" – in whose honour the country's right-wing Vienna ball is held annually. The clubs not only enjoy a reputation for heavy drinking but several still practise an antiquated duelling style conducted without full face masks. Some 4,000 Burschenschaft members are thought to support the far right.
The Freedom Party's increasing popularity recently led Strache to reject an invitation from a far-right student club, fearing he might be too closely identified with extremist views. In a bid to dispel concerns about his attitude to the Nazi persecution of the Jews, he also visited Israel's Yad Vashem Holocaust memorial. One Austrian Jewish leader said the spectre made him "want to throw up".