Linux – bindfs works, but not via /etc/fstab

I can do a bind mount like this:

bindfs -u target --mirror=target /home/source/import/target /home/target
umount /home/target

But it fails, if I try to do the same thing via /etc/fstab:

# fstab line:
/home/source/import/target /home/target  fuse.bindfs  mirror=target 0    0

Try to mount via /etc/fstab:

LANG=C mount /home/target

mount: wrong fs type, bad option, bad superblock on /home/source/import/target,
   missing codepage or helper program, or other error

   In some cases useful info is found in syslog - try
   dmesg | tail or so.

But dmesg does not contain a new entry.

target and source are the name of directories and the name of two linux users.

What is wrong?

Hints how to debug this are welcome.

Alternative solutions are welcome, too. All I want is that new files created by user target in /home/target are visible for user source in /home/source/import/target.