Most likely the contract has a section about what happens if you break it. Typically you would wave bye bye to your deposit, but other than that nothing should happen. 

A nice conversation with the landlord won't hurt. Explain the situation. In all probability, you'll get your deposit back in full. My experience so far was ok. All my landlords understand the need for foreigners to move at a moment's notice and agreed. This is better than skipping town leaving a bad name for yourself. Who knows, you might just go back to the same town again later and run into the landlord. Better to leave on a good note wherever you go.

My understanding is that you can get out of the contract if you find another tenant for the apartment or you pay the landlords half of the next agency fee plus any loss of rental income between you moving out & next tenant moving in. That's if you have an obliging landlord. Whatever happens you can basically kiss goodbye to the deposit you paid. Good luck. 

actually the landlord doesn't agree that i find a new tenent, he told me that either i'd stay or he keeps my deposit. The apartment was overpriced from the beginning but i hadnt choice that time (had to leave my friends apartment suddenly, he is chinese, because his brother needed it). So now after a couple of week