User want only to show the pseudo (identifiant) in forum
Can a user configure his/her account so that other users can NOT see her/his name, email..., only a pseudo (and access their profile) ?
welcome to the Redmine community!
AFAIK there's no option in core Redmine to do this.
The Administrator can set the user display format globally to their login name but there is no option to hide a users profile to other members. There is also a personal setting in the users menu to hide the email address to other users.