Protesters repeatedly disrupted a concert by the Israel Philharmonic orchestra in Paris on Thursday, brandishing flares and sounding alarms that caused brief panic in the crowd and led musicians to leave the stage.

Authorities said four people were detained.

The French government decried the orchestra disruption as antisemitic and an attack on freedom of cultural expression.

Inside the concert hall, witnesses described a performance punctuated by eruptions of chaos, and solidarity in the audience for the musicians trying to finish the show.

Video from inside shows concertgoers standing up, some recoiling and some trying to subdue the protesters as red smoke and shouts fill the venue.

The musicians eventually returned to the stage to finish the concert.

Pro-Palestinian activists also demonstrated outside Thursday night's performance at the Paris Philharmonic concert hall, the latest example of tensions over the war in Gaza spilling over into protests in Europe.