1. If you purchase the flat, it will be registered in your name as you the purchaser and builder as the seller.However you can insist the builder and the NRI investor to sign a Tri-party- agreement separately which can mention about the details of the deal the money transaction and the amount adjustments etc. , to avoid any future claims.The NRI can sell you from a direct transfer from builder to you
2. The builder will be the seller in this case as there is no Registration took place.
2. it is usually the rate at which the buyer needs to deduct tax is 1% and it may go up to as high as 20% if the seller does not disclose his PAN. This rule also covers the property purchased through home loan.
Under sec.194-1A, of the act, any sum paid by way of consideration for transfer of any immovable property (other than agricultural land) is covered under section 194-IA, provided the consideration for transfer of an immovable property is not less than Rs. 50 lakhs.
No deduction shall be made where consideration for the transfer of an immovable property is less than fifty lakh rupees.
4. The Tax/ TDS shall be decided on the consideration amount mentioned the sale deed
5. To complete the registration make sure that you get all the documents pertaining to the building along with the sale agreement/ sale deed as it is applicable in Kolkotta, make sure that you get n NOC from the builder that the flat is clear of all encumbrance, you will not be able to get nay details of mortgage from the registrar office as it is not yet registered.The deed for Registration of the sale is usually prepared by the builder and you can get an advocate to scrutinize e it. Once the documents is prepared make payments of stamp duty and registration charges as required and go for the registration.
Ultimately you as a purchased need to keep due diligence in buying a property, so its tile, permissions, developmental rights,occupancy certificate, completion certificate, permission from different local and Government authorities etc have to be in place.All these can be checked before entering into a deal.
So ask for the copies of set of documents get it scrutinized with a local property lawyer and proceed further.