Does notary document have a legal value ?

Isn't it a valid contract under Contract Act? If no,  why no ?

The signature and stamp of Notary on the agreement also means notary has attested the signatures of the executants of the agreement.

What is the reason that legally prevents Mr A from sueing Mr. B ?

I agree with Democratic Indian. Notary acts under Notary Act.

Incase If " Mr.B" want to sell his flat to "Mr.A", Agreement to sale is done they registered the sale aggrreement at sub-registrar office.

some time the rule of law is bound to become out of context when the issue is under the care of judiciary.A Notary document from that point of time can be made available to the competent authority with a personal copy till a modified government sanction is issued. In the present day context,Aadalat cell takes care of service matters to the extent possible.At a later stage, the relevant government letter will be found attached after consulting the Department.Regards slakshmanrao3@gmail.com

Very recently Central Government has issued an Office Memorandum dated 31.03.2015 which covers the jurisdiction issues also,Which can be claimed from Pension Grievances New Delhi if considered necessary.With regards slakshmanrao3@gmail.com

Does Notary Document have a legal Value...The answer is yes...

Things will depend on the basic validity of the sale agreement. Notarising does not by itself strenghten the validity. The aggrieved party can go to court irrespective of whether it was notarised or not so long as it contains all the elements of an agreement. In some States full stamp duty has to be paid at the agreement stage itself. In such a situation it is difficult to go back on such an agreement.

Sec.17(1A) of the Registration Act,1908 declares that an unregistered contract shall not be pressed into service for the purpose of sec.53 A  of the Transfer of Property Act,,1882. Sec.17(1A) of the Registration Act,1908, does not whether in specific terms or by necessary intent, prohibit the filing of a suit for specific performance based upon an unregistered agreement to sell, that records delivery of possession or is executed in favor of a person to whom possession is delivered and the proviso to sec.49 of the Indian Registration Act, 1908 put paid to any argument to the contrary. The proviso to sec. 49 of the Registration Act legitimises a contract to the extent that, even though unregistered, it can form the basis of a suit for specific performance and be led into evidence as a proof of the agreement or part performance of a contract.  Notarised agreement can be used as evidence in a suit for specific performance of contract.

Answer to the Menu captioned is !!!Yes!!!

Thanks for appreciation of my views on the subject.

I agree with the views and opinions of senior learned counsel respected Roy Sir stating that the unregistered sale agreement  but duly notarized can be used as an evidence in a suit for specific performance  of contract, however, the court can decline the enforcement of the contract being unregistered but can always pass an order for alternate relief to refund the consideration amount received if found  satisfactorily.