Copying the solution from this guide with my modifications:
Open a Terminal and navigate to the directory containing your backups. This folder contains all of your files archived into many .gz files. Mine was in a folder called
multivol_snapshot. Unpack all the archives with the following command:
for t in duplicity-full.[yournumbershere].*.difftar.gz; do tar xf $t; done
This might take awhile. I had 138GB of data which took five hours to untar.
Running this will give you your files and folders back in the correct structure with one caveat: All of the files are split into smaller pieces. You can join these files back manually easily by running the following command:
cat * > examplefile.txt
However, if you have thousands of files doing this could take a very long time. David Huss wrote a Python script called duplicity_joiner.py to make this easier. Download it here.
To run it, you need python and tk. Install this by running:
sudo apt-get install python-dev
sudo apt-get install python-tk
Using this script you can select the folder where to restore your files, with one caveat: This script doesn't maintain the folder structure. So, if you have many folders and files with the same name there is a possibility that they will be overwritten.
I have rewritten the script to address this. It will preserve the folder structure but can result in very long folder paths. Download it here.