The narrator interrupts the story to comment, judge, give an opinion or speak directly to the reader.
In Madame Bovary
human speech is like a cracked kettle on which we bang out melodies to make the bears dance, when what we meant was to move the stars to pity
The narrator stops the account and comments in a tone of pronouncement: "human speech is like a cracked kettle." The opinion about language comes from outside the characters and answers the judgment Rodolphe makes of Emma's love.
Part II, Chapter 12, the narrator
because a request for money is the coldest and most devastating of all the storms that can break upon love.
Part III, Chapter 8, the narrator
the wood of the coffin, struck by the stones, made that formidable noise which seems to us to be the reverberation of eternity.
Part III, Chapter 10, the narrator
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