In A Tale of Two Cities, what are 3 quotes that convey Dickens's attitude in Book 3, Chapter 15?

Dickens is very specific about his view of the guillotine in the French Revolution.  He considered the guillotine a terrible travesty of justice.  Since he was about to send one of his main characters to his death, Dickens took some time to insert commentary about the guillotine.

Along the Paris streets, the death-carts rumble, hollow and harsh. Six tumbrils carry the day's wine to La Guillotine. All the devouring and insatiate Monsters imagined since imagination could record itself, are fused in the one realisation, Guillotine. (3: 15)

Sydney Carton agreed to switch places with Charles Darnay and die in his place at the guillotine.  It was a romantic gesture, and one rife with meaning for Dickens.  Dickens believed that while the poor people suffered under the regime of the aristocrats, it did not justify the broad scale death and destruction that took place in the French Revolution.   Innocent people died, such as Carton.

Dickens also makes a comment about the revolution’s effect on the population in the future. 

Crush humanity out of shape once more, under similar hammers, and it will twist itself into the same tortured forms. Sow the same seed of rapacious license and oppression over again, and it will surely yield the same fruit according to its kind. (3: 15)

He is essentially saying that the revolution altered the course of history, and not in a good way.  The injustice of the revolution had a ripple effect.  This reiterates the warning he gave in the beginning of the book about revolutions in other countries like England being imminent.

Dickens comments that the scene of people going to their deaths at the guillotine occurs so often that people do not even notice it anymore.

So used are the regular inhabitants of the houses to the spectacle, that in many windows there are no people, and in some the occupation of the hands is not so much as suspended, while the eyes survey the faces in the tumbrils. (3: 15)

No one stopped them or stepped in to intervene, because they were afraid, and because they grew complacent.  They just let people go past them every day to their deaths.

Dickens made a career out of taking current events or historical events and sentimentalizing them.  Like Tiny Tim and Oliver, Sydney Carton’s sacrifice became symbolic of the French Revolution.  People felt sorry for both sides, because the peasants and the revolutionaries were both displayed with such sentimentality.