Hi,
 
Thanks for your rapid answer. We found the issue.
 
In fact, I use the client (more or less) as I should use the proxy. Sorry!
 
 params = {
  'profile_name':              raw_input(),
  'cmd':                       raw_input(),
  'server':                    raw_input(), 
  'port':                      int(raw_input()),
  'username':                  raw_input(),
  'key_filename':              '',
  'allow_share_local_folders': False,
  'share_local_folders':       [],
 
  'link':                      'adsl',
  'use_sshproxy':              False,
  'sshproxy_key_filename':     '',
  'sshproxy_host':             '',
  'sshproxy_tunnel':           '',
  'sshproxy_user':             '',
 
  'session_type':              'application',
  'geometry':                  '800x600',
  'convert_encoding':          False,
  'client_encoding':           'ISO8859-1',
  'server_encoding':           'UTF-8',
 
  'rdp_server':                '',
  'rdp_options':               '',
 
  'allow_mimebox':             False,
  'mimebox_action':            'OPEN',
  'mimebox_extensions':        '',
 
  'snd_port':                  4713,
  'snd_system':                'pulse',
  'kbtype':                    'pc105/us',
  'kblayout':                  'us',
  'printing':                  True,
  'pack':                      '16m-jpeg-9',
  'xdmcp_server':              'localhost',
 }
 reg_session_instance = x2go.X2goSession(**params)
 reg_session_instance.connect(params['username'], raw_input());#this was already wrong...
 reg_session_instance.start()
 stderr.write('Hand-shake over, nxproxy starts.\n')
 while reg_session_instance.is_running():
  gevent.sleep(1)
 reg_session_instance.terminate()
 exit()
 
And thus, I have no client to indicate the local Xserver, on ubuntu it works fine, but on windows...
 
How can I proceed the same way (without a parameter file) with a proper client to fit with the local XServer ?
 
Thanks again,
 
Pierre