Dear Joplin Community,
as far as I could find out, it is not possible for the user to choose a specific path when syncing with Dropbox, but it is limited to ‘Apps/Joplin’.
With that made configurable, the user would not only be able to control the structure of his/her files on Dropbox, but also use the same Dropbox account to sync different Joplin instances.
Thank you for working on that great app.
Best Regards,
Chillbird
As far as I know, Dropbox does not allow third party applications to do that for security reasons.
To get around it though, you can use joplins file system sync and point it to any folder you have with Dropbox. although that’s probably not an officially supported workaround
Thank you John for the answer,
yes this workaround should work on Desktop, but not for example on Android.
If the restriction is given by Dropbox, I guess have to live with it 
There are some third party Dropbox apps on Android that will give you this functionality. It’s probably not the smoothest, but it’s possible.
Thanks for the hint.
Regarding the restriction of Dropbox: I remembered Boxcryptor, a Software that can manage E2EE for different Cloud Providers, including Dropbox. Through its client, one can choose to encrypt any of the files and folders stored on Dropbox and the client downloads, ecrypts and reuploads it, so the client has access to every file.