Your targets, Viktor Novikov and Dalia Margolis, are the hosts of a Sanguine-sponsored fashion show, which is held at the couple's palace in Paris. It is a multi-event gala, with Viktor entertaining guests on the ground floor and Dalia playing emcee to discrete guests at an auction on the top floor. Despite the crowds and high security, eliminating these two is an easy task — provided you're familiar with the palace's layout.
Head to the basement via the door underneath the main stairs.
At the lockers, don the waitstaff disguise.
Go to the hallway perpendicular to the kitchen and learn the Bare Knuckle Boxer recipe.
Make your way to the main entrance of the surveillance room (the one with the large doors). Don't walk into the room just yet. You have to deal with a guard first. He walks back and forth between the mess hall and the surveillance room. When he either exits or is about to enter the surveillance room, subdue him and put him in the trunk nearby. Don't worry about the guards in the surveillance room. They shouldn't be able to see or hear what's going on.
Be sure to hide any gear dropped by those you subdue, since finding random weapons in hallways will make passersby suspicious.
Focus on the technician alternating between his desk and the server wall. When he walks to the server wall, enter the room and destroy the main surveillance computer. This will prevent cameras in the venue from tracking you.
Head upstairs to the first floor and make your way to the hors d'oeuvres prep room, which is adjacent to the bar. When you're in the prep room, grab the two rat poisons near the window.
Walk behind the bar and pretend to be a waiter.
When Viktor arrives, make him a Bare Knuckle Boxer and add the rat poison to the cocktail.
As he's drinking the cocktail, leave the bar and head for the men's restroom near the hors d'oeuvres prep room. Hide in the wardrobe until Viktor arrives.
When Viktor is puking in the toilet, exit the wardrobe and drown him. Hide his body in the wardrobe.
Use the nearby stairs and go up one floor. Subdue the technician at the top of the stairs.
When you exit the stairs, make a right, then a left, then two rights. You'll be in a large, empty room. Subdue the waiter distracted by his tablet. Don his outfit.
Be sure to drop any firearms beforehand, and then go to the wide set of stairs nearby. A security guard will frisk you. Go up the stairs when he lets you pass.
When you've reached the top of the stairs, continue toward the doors in front of you. Enter the room while crouching to avoid detection by the armed guard at the opposite end of the room.
While crouching to avoid detection, toss a coin to the far left side of the room distract the guard. Approach him from behind and subdue him. Hide his body in the wardrobe in the adjacent ladies' room.
Leave the ladies' room. Make your way through the auction room and onto the balcony.Get behind the bar.
Poison the drink at the bar.
Tend the bar until Dalia arrives and drinks from your poisoned glass. As she's drinking, leave the bar and return to the ladies' room. Hide in the wardrobe until Dalia arrives.
When Dalia is puking, exit the wardrobe and drown her. Hide her body in the wardrobe.
Discretely leave the venue using your exit of choice.