https://technet.microsoft.com/fr-fr/library/jj679892(v=ws.11).aspx
You can use Windows Server 2012 Foundation in either Active Directory® or workgroup environments to create up to 15 user accounts that can access and use the server software. Each
user account permits one user, using any device, to access and use your server software with
no client access licenses (CALs) required. In the Windows Server 2012 Foundation operating system, you will receive a warning message if you exceed the fifteen-user limit. For steps to remove user accounts from Active Directory, see
http://go.microsoft.com/fwlink/?LinkId=150361. For steps to remove user accounts from a workgroup environment, see
http://go.microsoft.com/fwlink/?LinkId=150362.
Remote Desktop Gateway (RD Gateway) enables authorized users to connect to virtual desktops, RemoteApp programs, and session-based desktops on an internal corporate network from any Internet-connected
device.
Windows Server 2012 Foundation supports a maximum of 50 RD Gateway connections.
In order to access a hosted application, such as Microsoft® Office,
a license for Windows Server 2012 Remote Desktop Services is required for each user account (not to exceed 15 user accounts) that directly or indirectly uses RD Gateway to host a graphical user interface, including using Remote
Desktop Connection (RDC) client. When using Remote Desktop Services, you may not install or use Remote Desktop Connection Broker or Remote Desktop Virtualization Host role services.
Bref, avec un peu de lecture : oui en RDS, 15 utilisateurs Max, CAL nécessaire si il s'agit d'applications distribuées que ce soit par Desktop Service ou par Application Service.
