It is implied the Erique is in love with Christine

None.

A man is strangled to death. Mildly violent.

A man gets acid thrown in his face, burning him. However, we never get a good look at his face until the very end. And even then, it's not that shocking.

Two women are killed off-screen. (We only hear screams.)

A man is strangled. Once again, it's mildly violent.

A Chandelier falls on the audience in the Opera House, but no graphic violence is shown.

A man is (presumably) crushed to death by falling boulders and rocks.

Because of the time of it's release, there are no curse words or slurs used.

None.

Younger viewers might find the unmasking scene to be mildly frightening. But otherwise, the film is very tame.