Everytime I try any command of the type 

/usr/bin/dnf update
/usr/bin/dnf --help
sudo /usr/bin/dnf (whatever) it crashes on me

I can't tell what the problem is, but I get this trace from python...

Traceback (most recent call last):
  File "/usr/bin/dnf", line 36, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 198, in user_main
    errcode = main(args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 84, in main
    return _main(base, args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 117, in _main
    cli.configure(map(ucd, args))
  File "/usr/lib/python2.7/site-packages/dnf/cli/cli.py", line 1007, in configure
    self.optparser.usage = self.optparser.get_usage()
  File "/usr/lib/python2.7/site-packages/dnf/cli/option_parser.py", line 273, in get_usage
    usage += "%-25s %s\n" % (name, summary)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 40: ordinal not in range(128)