project_gtd can't display "My Tasks" in non-ascii languages

Step to reproduce from scratch:

1 - create a new database with "french" as default language
2 - install module project_gtd
3 - try to access Projects/My Task view

I'm using rev corresponding to 6.1 tag.
I'm providing a video to show the bug.

Here is the exception I get:

Traceback (most recent call last):
  File "/home/vaab/dev/python/openobject-server/openerp/netsvc.py", line 361, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/home/vaab/dev/python/openobject-server/openerp/service/web_services.py", line 604, in dispatch
    res = fn(db, uid, *params)
  File "/home/vaab/dev/python/openobject-server/openerp/osv/osv.py", line 167, in execute_kw
    return self.execute(db, uid, obj, method, *args, **kw or {})
  File "/home/vaab/dev/python/openobject-server/openerp/osv/osv.py", line 121, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/home/vaab/dev/python/openobject-server/openerp/osv/osv.py", line 176, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/home/vaab/dev/python/openobject-server/openerp/osv/osv.py", line 164, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/home/vaab/dev/python/openobject-addons_old/project_gtd/project_gtd.py", line 118, in fields_view_get
    res['arch'] = res['arch'].replace('<separator name="gtdsep"/>', search_extended)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 21: ordinal not in range(128)

DIAGNOSTIC

In the failing line:

   res['arch'] = res['arch'].replace('<separator name="gtdsep"/>', search_extended)

"res['arch']" is encoded in utf-8, but "search_extended" is unicode. In english language, this is not a problem as "res['arch']" can be decoded from utf-8 to unicode using the "ascii" codec. This is not the case for french language, if it uses accentuated characters, which is the case here with the word: "Tâche" for example.