The deposit will be due at the time the preliminary contract is signed. If you are not purchasing a 1 euro house, the deposit amount is determined between you and the seller.
a. If a buyer cancels after the deposit has been paid, they forfeit the deposit. If the seller cancels, the seller returns the deposit AND pays the buyer an equivalent amount of the deposit.
b. The deposit can be in the form of an international wire transfer or bank check. Note that the contract can be forfeit if the deposit is not received within the specified time. Typically for international purchases, the Agent will arrange sufficient time to process an international wire transfer.