If I work on a database commissioned on a second server, can I recover the user rights defined in the first base?

Yes. From the Client connected to the second commissioned base, launch the command File > Utilities > Recover the users and point to the *.profiles file, located in the following directory: C:/Program Data/IndexEducation/EDT/SERVEUR/VERSION en cours/FR/Serveurs. To access the Program Data folder, make sure that the option Display the hidden files, folders and drives is selected on your PC ( menu Start > Control Panel > Appearance and Personalization > Folder options > Display).