On this page of the guide you can find a walkthrough for Sleepless quest. Following Julien Raimond's instructions, you must find out what planters inhabiting Hotel de Massiac are planning.
The mission is received at Cordelier Convent, after the conclusion of To Les Invalides story quest. Julien Raimond is the quest giver. Talk to him.
Hotel de Massiac
Start by traveling to La Cite. The path leads through Les Halles - you'll recognize the path, as it was traversed during In Search of Abbot Gregoirestory quest. When you leave the marketplace, follow the path to the intersection. Turn left, into the gap between the barricades.
Go further down the road. Here you'll encounter a Trumpeter (more about this type of opponents in Musicians) Further ahead, in front of a barricade, there is a Musketeer (more on this type of opponent in Guards page of the guide). Defeat him and use The Alchemist's Ram on the gate. Walk through it.
There is another Trumpeter behind the gate. Continue along the path. At its end, you'll face a Heavy Prototype (more on this enemy in Protoypes page of the Opponents section) Once the danger is gotten rid of, use The Bishop's Hook to raise yourself to the platform. Use it.
Jump down at nearest possible occasion. Preferably using the canopy on the left. There is a Musketeer here. Further ahead, you'll encounter a Violinist (more on this opponent in Musicians page of the Opponents section).
Now get past the barricade. There is a Heavy Prototype and a Butcher on the other side (more on this enemy in the Cooks page of the Opponents section.
There are 2 possible paths now. Nevertheless, they both lead to the same place. However, the right one is shorter. On the other hand, the longer route allows you to face enemies one by one. The shorter route will see you face a larger group of them, which means a more difficult encounter. There is a Violinist (more on them in the Musicians page), Courier, Ice Squire, and a Hoplite (more on these enemies in the Opponents chapter). to face here.
Once the area is clear, climb the crates to reach the square before the hotel. Here you'll have to face a Courier and a Statuary Ram (more on this opponent in Rams page of the guide)
Stand with your back turned to the gate, and you'll see a balcony on the left that you can climb. Follow to the next balcony using The Selenite Momentum (the painting will serve as a platform)
There is a letter inside the room. Read it to continue with the task.
If you want out of the palace, enter the balcony again. Jump to the balcony on the left (looking from the room you are in), then use The Selenite Momentum to get behind the fence.
Opposite the gate to the hotel, however, there is a shortcut with which you will unlock the road back to Les Halles.
Travel to Les Invalides. After arriving with the carriage, go to the park before Vaucanson's workshop. The path should be familiar, as you've visited this location in the course of The Master of the Machines story quest.
However, here things go different. To the left of the main gate is a weakened wall that can be destroyed. Do so. There is a Statuary Ram nearby, so watch out. Go through the breach and enter the building behind it. You will trigger a cut-scene. After it, you will be forced to face an Ice Square.
Once the opponent is defeated, use the hook to reach the platform under the roof. Follow the sidewalk to the next building. Jump down and head to the square. A Lumberer awaits you there (you can read more about this opponent on the Labourers page of the guide).
Once the area is clear, climb the footbridge to the roof of the buildings. Now use The Selenite Momentum to reach the platform shown in the screenshot.
You'll need to face 2 Forgers (more on them in the Labourers page of the Opponents section) and a Courier here.
Don't forget to check out the chest found right from the workshop. Inside it, you will find a Carriage Token. You can use it to instantly teleport to the carriage.
Enter the building. On the left, on the table near the entrance is a letter that you must read. Now you can return to the quest giver - Raimond - found at the Cordelier Convent.