There is a sound alarm that triggers above 65 db (about the volume of a normal conversation ) and sends a notification to a security guard that will come check and fine you 100€. While I understand the need to be quiet and respectful of the neighbors, the alarm felt really overkill and invasive. In addition the check in is kind of confusing where you have to either dowload an app, call Geert or a neighbor to open the building's door. Other than that a good apartement and Geert was extremly helpful and responsive.