casting from Filmon to TV in France
Looking at the 'Chromecast specs., I don't think you can log on to Filmon (or Camposat). I decided on an ethernet-connected laptop (closed and with screen off) discretely placed next to the TV with keyboard and mouse at hand. The laptop also feeds far more than just internet TV, of course.
Incidently I also haven't been able to connect to Filmon with my satellite receiver, which has an ethernet connection.
If anyone has used Chromecast to get Filmon I too would be interested to hear of it.