Comment 1 for bug 923824

This is indeed due to loading a particular library both through GIR and through a static module. dbus can be mixed quite fine with Gtk, though; if you only use client-side d-bus (i. e. making calls), using Gio.DBusProxy will work fine, but if you want to export objects to the bus, you currently have to use the static "dbus" binding.

I advise to temporarily modify /usr/lib/python2.7/dist-packages/gobject/constants.py to say

raise ImportError("no static plz")

somewhere at the top, then you will get a proper backtrace and can easily identify the culprit.