Are you liable to pay Zakat on the 1994-booked apartment given to your sister’s family?

I booked an apartment in 1994 to live and had no intention to sell or rent. Due to the delay the company handed over me the apartment in 2007. In the meen time I bought another apartment in 2000 where I am living now with my family. I have given that apartment (that I booked in 1994) to my sister to live with her family (husband and 2 kids) who are not financially well. I do not take any rent but invested inrennovation for them to live. I am the owner of the apartment. Kindly advise if I am liable to pay Zakat on this apartment under the current circumstances. Jazakallah.