export PYTHONPATH=/usr/lib/python3.3/site-packages

in my .zshrc / .bashrc

This caused the error. Since it is needed for powerline I might just switch to its python2 version then.

This is what I get: Traceback (most recent call last): File "/usr/bin/deluge", line 9, in <module> load_entry_point('deluge==1.3.6', 'gui_scripts', 'deluge')() File "/usr/lib/python2.7/site-packages/deluge/main.py", line 132, in start_ui UI(options, args, options.args) File "...