When renting a house in The Netherlands, it is customary that you pay for a deposit to the landlord after signing the lease contract. The amount of the deposit is often 3x the monthly rent. If the lease fee is for example 2000 euro, then you must pay 8000 euro at once: 2000 for the lease and 6000 for the deposit.
The 6000 deposit is used to pay for possible damages on the property when you terminate the contract. Because your deposit is with the landlord you have little control over the amount that will be deducted from your deposit. This often results in a quarrel about the cause of the damage and the amount that will be deducted for repair work. To many expats this deposit system is a burden.