In the rich text editor:
@luciix
In a comment:
[luciix](https://chowlings.com/user/luciix)
For Names and Avatars:
In the rich text editor:
%luciix
In a comment:
[![luciix's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/luciix) [luciix](https://chowlings.com/user/luciix)