How I can know the IP address of other users logged at the same remote machine?

Try the w command, part of the procps package.

$ w
 21:12:09 up 6 days,  7:42,  1 user,  load average: 0.27, 1.08, 1.64
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
h3xx     pts/11   192.168.1.3      21:12    2.00s  0.04s  0.04s -bash

The who manpage on my Debian Linux system shows there's an --ips option to display IPs instead of hostnames.