Weigh the phone in hand. For comparison, take a similar model, which you are sure. Chinese phones usually weigh much less than their European counterparts.
View Russian menu in your phone. If it is Chinese, you'll know it's a bad translation of all instructions into Russian.
If you have access to the Internet, find out the IMEI number of the phone. For this, type it a combination *#06#. Display will show serial number. Roll it into a string denotes the entry on the website check http://www.numberingplans.com/?page=analysis&sub=imeinr. Click analyse and get all the information about your phone, including the country of origin.
In the Chinese model, typically a TV, two or even three SIM cards. However, many applications do not work or are not available for download.
Look for a removable battery cell. Usually, data about country of origin written there.