The parking lot behind the flat is closed off by a gate. Do you need access to the parking lot for a couple of days? Then you can request a temporary parking key according to the rules set out below.
Keep in mind that there is a limited amount of parking keys available. Send in a request ahead of the period where you need to access the parking lot to make sure that there will be one available for you.
Do you have your own car? Then you can request a key for long term use via Lefier.
Rules for borrowing a parking key: