New York's Metropolitan Opera led by Placido Domingo on Saturday mourned the victims of the attacks in Paris with an unscheduled performance of the French national anthem.

Ahead of a matinee of Puccini's "Tosca," Domingo conducted the orchestra in "La Marseillaise" as the Metropolitan Opera Chorus sang the words in French on stage.

A slip of paper was put in all programs at the premier US opera house with the lyrics to the anthem and an explanation that the song was "a show of our solidarity with the citizens of France."

A music venue, the Bataclan, suffered the deadliest toll Friday night as assailants killed at least 129 people in a coordinated rampage around Paris.

New York, scarred by the September 11, 2001, attacks, has come out to remember the victims in Paris.

One World Trade Center, New York's tallest building which opened last year near the site of the fallen twin towers, lit up Friday night in the French flag's blue, white and red tricolor, while the Empire State Building went dark as a sign of mourning.

Domingo, considered the world's most famous opera singer, has returned to the Metropolitan Opera after missing initial "Tosca" performances due to gallbladder surgery.