Comment 8 for bug 633101

Same problem here, using duplicity 0.6.18. This was from a 'collection-status' command:

Local and Remote metadata are synchronized, no sync needed.
Traceback (most recent call last):
  File "/usr/bin/duplicity", line 1404, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1397, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1277, in main
    globals.archive_dir).set_values()
  File "/usr/lib/python2.6/dist-packages/duplicity/collections.py", line 691, in set_values
    self.get_backup_chains(partials + backend_filename_list)
  File "/usr/lib/python2.6/dist-packages/duplicity/collections.py", line 814, in get_backup_chains
    map(add_to_sets, filename_list)
  File "/usr/lib/python2.6/dist-packages/duplicity/collections.py", line 804, in add_to_sets
    if set.add_filename(filename):
  File "/usr/lib/python2.6/dist-packages/duplicity/collections.py", line 93, in add_filename
    self.set_manifest(filename)
  File "/usr/lib/python2.6/dist-packages/duplicity/collections.py", line 124, in set_manifest
    remote_filename)
AssertionError: ('duplicity-inc.20121213T042623Z.to.20121214T051524Z.manifest.part', 'duplicity-inc.20121213T042623Z.to.20121214T051524Z.manifest.gpg')

As above, removing the file makes the problem go away.