Hello Kumar,
The only tool we have for user activity tracking is Auditor, you can use it to monitor users activity (logins, logoffs, reports scheduled, etc).
The Administrator's Guide has more details on exactly how to use Auditor within the product.
Notification when scheduling https://service.sap.com/sap/support/notes/1544644
There also some scripts helping to enable email notification not for specific user(s) activity but for scheduled reports...
https://service.sap.com/sap/support/notes/1741520
https://service.sap.com/sap/support/notes/1741585
https://service.sap.com/sap/support/notes/1613009
In 4.0 you can use Alert notifications for Crystal Reports
https://service.sap.com/sap/support/notes/1875765
https://service.sap.com/sap/support/notes/1875795
Kind Regards,
Monia.