Delete branch start with "-"

["Yoann Hervé" <yoann.herve.ext@makina-corpus.com>]

Hello,
by mistake I have created a branch with a "-" at the beginning of his 
name, and now I can't delete it.

 git branch -d -f
 error: unknown switch `s'
 usage: git-branch [options] [-r | -a] [--merged | --no-merged]
    or: git-branch [options] [-l] [-f] <branchname> [<start-point>]
    or: git-branch [options] [-r] (-d | -D) <branchname>
    or: git-branch [options] (-m | -M) [<oldbranch>] <newbranch>

 Generic options
     -v, --verbose         be verbose
     --track               set up tracking mode (see git-pull(1))
     --color               use colored output
     -r                    act on remote-tracking branches
     --contains <commit>   print only branches that contain the commit
     --abbrev[=<n>]        use <n> digits to display SHA-1s

 Specific git-branch actions:
     -a                    list both remote-tracking and local branches
     -d                    delete fully merged branch
     -D                    delete branch (even if not merged)
     -m                    move/rename a branch and its reflog
     -M                    move/rename a branch, even if target exists
     -l                    create the branch's reflog
     -f                    force creation (when already exists)
     --merged              list only merged branches

How can I delete it ?

Thanks,
Yoann