"I was leaving the national opera when a couple of fundamentalists, a man and a woman I believe, rushed towards me, tore my hat off and threw a container full of dog poo at me..." said Jean-Michel Ribes after the attack on Tuesday evening, French daily Le Figaro reported.
In December, Ribes had received death threats when the theatre he manages, the prestigious Rond-Point theatre in Paris, put on a controversial play about Christianity.
Christian radicals protested the play called "Golgota Picnic", directed by an Spanish-Argentinian director Rodrigo Garcia. The play features a trash crucifixion of Christ who is referred to has "el puto diablo".
But Paris theatre critics have said it was absurd to call it anti-Catholic or blasphemous, The Guardian reports.
The director of the Nancy opera said he deeply regretted the assault on Ribes, saying it was "shocking and dreadful". Ribes was in Nancy to give a press conference on new play he was working on.
However Ribes seems to have taken the attack with a pinch of salt and joked that the two aggressors had probably disliked his press conference.