08 April 2012
As per section 70 of Finance Act, 1994, When an assessee is liable to pay service tax (whether as a service provider or service receiver) is required to file half yearly service tax return in form ST 3.
In case of your client, if he is required to pay service tax under reverse charge mechanism, he is required to file service tax return in Form ST 3 though the value of services provided by your client is less than 10 lakhs. Such threshold limit does not apply to reverse charge mechanism.