The 2005 version of the Opera Ball drew fewer protesters than usual.
Police recorded about 20 demonstrators in areas near the State Opera, where the ball - the top event of Vienna's social calendar - was held Thursday.
Among the 4,500 guests was former Spice Girl Geri Halliwell, who was invited by a wealthy Vienna businessman who brings celebrities to the ball in an attempt to attract publicity.
Mezzo-soprano Elina Garanca from Latvia and tenor Marcelo Alvarez of Argentina performed.
Police searched several people but made no arrests. Past balls have attracted larger crowds who have protested the exorbitant display of wealth.
The area surrounding the State Opera had been cordoned off as a security measure, and streetcar and bus traffic was interrupted for several hours around the centrally located opera house.
Tickets to the ball sold out long ago at prices starting at $280.
