Parking problem

Good morning. Cars from the mechanic's workshop are constantly parked in front of the houses. Therefore, the residents here cannot use their own private parking lot. We have already signaled to them several times not to park here, but nothing happened. Currently, the blue car has been parked in front of the neighbor for days and he has to park elsewhere. I would like to know where I can go with this problem so that the problem goes away. Thank you very much