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