that should be ok under 220V.

Voltage may be compatible, but local radio emission regulations most certainly are not. This is true for both powerline and WiFi. You may commit a serious offence in that country, and yes, there is quite some potential it won't go unnoticed: Powerline communications exclude certain frequencies in each part of the world, namely those that are used for emergency, police, ambulance, and military radio. Run your foreign PLC in an unfortunately placed house, and you'll put one of those out of the air.