@Eliasrr wrote:
I thought that the dropbox-folder on my computer was a "cloud-folder", but that doesn't seems to be the case?
No, that's not the case. The Dropbox folder is a regular folder like any other and anything you place in it takes up space on the drive, at least initially. After a file or folder has synced to your account it can be set to Online-only so it no longer takes space on the drive.
You can also use Selective Sync to remove the local copy of a folder while leaving it in your account online, though they will no longer appear in the Dropbox folder.