Comment 5 for bug 1055356

I suppose you can run 'duplicity verify' to trigger the check you want, possibly with the --compare-data option to force comparison of the data itself (rather than of the filesize and timestamp as I suppose the default is).

Grep 'duplicity verify' in the output of a verbose manual backup 'DEJA_DUP_DEBUG=1 deja-dup --backup' to see the check that Déjà Dup runs after the backup, and that Michael mentioned in comment #1.

Beware that he advised against relying on a unique Déjà Dup/duplicity backup when upgrading or reinstalling systems, which seems to be your use case: https://mterry.name/log/2011/09/19/backups-and-distro-upgrading