My uncle gave me an apartment some years back but recently he has been declared bankrupt. Will I have to give up the apartment?

Not necessarily - it all depends on whether he was solvent at the relevant time, and whether title of the apartment has been transferred into your name. Gifts given between 2-10  years before the person making them was declared bankrupt still 'hold' if the recipient can prove that the former was solvent immediately after giving them, and that rights in the property have been transferred.