This is a very annoying stupidity that simply exploit the demand by many landlords as seen in the past few years since there are flats and villas, are plety available unoccupied waiting like nightingale dreaming for water and finally a new uncommon system is intruding in practice as in UAE. I am afraid very soon this epidemic get infected to all building holders.

35% decline is attractive if not it was elevated in advance to recover by the tricky rental method. make sure, all documents including landlords full details to be verified personally and his name with ID is verified as genuine, and not a third party is involved in the deal.
It is better to consult with a legal adviser to get more better vision and lawfull openion before signing the contract since one year advance is too much and is not heard in Doha ever some is collecting it except certain corporate occupation of big towers etc is contracted this way. Good luck.