Down payment
The down payment is the money the buyer puts into the purchase from their own funds, without borrowing it: savings, a gift, the proceeds of a sale.
Banks generally expect it to cover at least the purchase costs (registration duties, notary, arrangement fees), and sometimes part of the price. The larger the down payment, the easier and cheaper the loan.
In Luxembourg, the share of the price a bank may finance is regulated: in practice, that is what sets the minimum down payment expected for each buyer profile.