`bzr ls FILE` fails with directory error

I want to know file-id of one file and compare that id with fileif of file from another tree.

C:\Temp>bzr init 2
Created a standalone tree (format: 1.14)

C:\Temp\2>echo > foo

C:\Temp\2>bzr add
adding foo

C:\Temp\2>bzr ci -m1
Committing to: C:/Temp/2/
added foo
Committed revision 1.

C:\Temp\2>bzr ls foo --show-ids
bzr: ERROR: [Error 267] The directory name is invalid: u'C:/Temp/2/foo\\*.*'

Help for `bzr ls` has no mention it accepts only directory names though:

C:\Temp\2>bzr help ls
Purpose: List files in a tree.
Usage: bzr ls [PATH]

Options:
  --from-root Print paths relative to the root of the branch.
  -i, --ignored Print ignored files.
  -k ARG, --kind=ARG List entries of a particular kind: file, directory,
                        symlink.
  -v, --verbose Display more information.
  -R, --recursive Recurse into subdirectories.
  -V, --versioned Print versioned files.
  -u, --unknown Print unknown files.
  -h, --help Show help message.
  -q, --quiet Only display errors and warnings.
  -d ARG, --directory=ARG
                        Branch to operate on, instead of working directory
  --usage Show usage message and options.
  --show-ids Show internal object ids.
  -0, --null Use an ASCII NUL (\0) separator rather than a newline.
  -r ARG, --revision=ARG
                        See "help revisionspec" for details.

See also: cat, status

For me PATH is generic term, am I misunderstand something?

So either this is bug in ls, or help for ls should be improved.