All other answers did not work. This is the one that worked for me:

 sshfs REMOTE_USERNAME@REMOTE_HOST:/remote/dir/path/ local_mnt/ -o umask=003 -o <OTHER_OPTIONS>


This option is important: **umask=003**

Set this to whatever rights you want to provide to the respective local directory/file. Here, 003 means: 774 (which is: 777 - 003).
This allows the user and group to read, write and execute the files in the directory, others to only read them. It also applies to files that will be created in the future.
More info here: [Ubuntu: fuse MAN pages][1]


 [1]: https://manpages.ubuntu.com/manpages/xenial/man8/mount.fuse.8.html