There are a series of killings having place in a theater the days before an opera makes its debut. The protagonists are an hysterical female actress and the detective in charge of the investigation. The movie would be horror/comedy in terms of genre. Sorry for the bad english
Dario Argento’s (Terror at the) Opera (1987)?
http://www.imdb.com/title/tt0093677/?ref_=fn_al_tt_1
yes! thank you
Solved.