Example how to list installations by segmentParams

Hello,
from the API description i can’t figure out how to properly filter my installations by segmentParams.
The doc states it should be sent as JSON but it is a GET request. Is it still a query parameter?
Could you provide me with a full example? That would be awesome!
When i omit the filtering i receive a 404 with message: “The given applicationId does not match the application from the access token.” How can i fix that?
Thanks in advance,
Jan