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