Installation:
1. Copy paste in ACU.exe folder.
2. Press Home key while in game and select Assassin's Creed Unity French Revolution Guillotine 1789 Ultimate Reshade Preset from the home tab of the reshade by using  the blue arrow keys by clicking with left mouse button. The game will freeze while loading the effects for few seconds. After effects are enabled, press Home key again to exit.
3. Done.

Other info:
Effect toggle - Scroll Lock key
Reshade settings - Home key

Cheers and Enjoy!!