Cabaret - Novigrad
Quest Giver: Automatically accepted after A Poet Under Pressure
Other Requirements: N/A
You receive this quest immediately upon completing the A Poet Under Pressure Story Quest. The first thing you have to do for this quest is to travel to the Rosemary and Thyme in Novigrad, the brothel that Dandelion owns, and speak with him there.
He'll update your quest and send you to Madame Irina to borrow a prop sword from her. Once you've obtained the prop sword you'll have to meet Dandelion outside of Sophronia's house after dusk, 9pm or later is what worked for me. Dandelion will fake duel you and you get to choose whether or not you want to let him win. What you choose has no bearing on any future events outside of the dialogue in this quest.
Whatever you've chosen, once the fight is over with Dandelion you'll be tasked with returning to the Rosemary and Thyme and meeting Dandelion there in the morning. In the morning Dandelion won't be there though and the interior decorator will force you to make a decision about how you want the interior to look. Again, you choice doesn't matter and if you let Priscilla choose she'll choose randomly. Pick whichever you want to get your quest update.
Once the conversation is over you'll be tasked with finding Dandelion - head over to your quest marker on your map and speak to Dandelion who is pounding on a door. Use your Witcher Senses to find the key to open the door under a bucket near the front door. It doesn't matter how you handle the conversation inside the house, let Dandelion talk or beat him up, the outcome is the same.
Afterwards you'll have one last thing to do, collect the placards for Dandelion. Head to the artist's house (marked on your compass/map, follow the white dots) and you'll find bandits here ransacking the place. Beat them up to learn where Rautlec is at, Vegelbud Residence to the east of Novigrad.
You'll have a few different options to choose from, you'll only get the placards if you choose to pay off the artist's debt or if you win the race. The fastest way to end this is to just pay off the 200 Crowns he owes, it's barely anything anyway and you'll get EXP for choosing this option.
When you return to the Rosemary and Thyme you'll complete this quest. You'll also be thrown immediately into the very next quest called Carnal Sins.