Here is the full list of all 41 Lamplight City achievements.
Every friendship has one
Eavesdropped on every conversation
Ended up in jail
Played through the entire game without opening the casebook
Checked yourself into Riverview Asylum
Accused Albert Martin of Madame DuPrée's attempted murder
Accuse Arthur Devins of kidnapping the Harris baby
Concluded that Desiree Lathan's death was due to spontaneous human combustion
Accused Jimbo of murdering Ronan L'Espaye
Accused Margaret Andrews of murdering Desiree Lathan
Accused Malcolm Harris of kidnapping his own son
Declared a case unsolvable
Accused Guy Dumas of Madame DuPrée's attempted murder
Correctly solved every case
Found every single clue and document in the game
Sang a popular drinking song
Told Adelaide the truth
Tricked Jonas Usher
Fixed the boiler without any help
Spoke with Roland Deveraux
Revealed Madame DuPrée's true nature
Got kicked out of Sabine Martin's apartment
Kept your promise to Mrs. Hanbrook
You're so annoying
Completed the game
Confronted the Justice Killer in his own home
Accused Tom Puffin of murdering Ronan L'Espaye
Discovered the truth about the cooping scheme
Read every book in the game
You voted!
Told Patrick a story
Accused Roger DeVay of murdering Desiree Lathan
Showed Desiree's ashes to someone who wasn't Dr. Edwards
Gave Charlotte Robineaux a music lesson
Successfully located Linda Walker
Accuse Linda Walker of kidnapping the Harris baby
Told Angela Maxwell about your problems
Learned about Mrs. Davis's hobby
Accused Juliette Montgomery of Madame DuPrée's attempted murder
Played a familiar melody
Read Madame DuPrée's poems