Gryphon seem to say the amp needs 10A minimum at 230V, they also recommend a power conditioner isn’t used. Once it comes back from Denmark suitably adjusted then maybe try it with you existing wiring and without a conditioner as long as it has a earth, not all French living rooms have one depending when they were wired.
Our apartment in Montpellier (1970s build) had earth connected in the kitchen, bathroom (on a 32A socket for a washing machine) and to an outside socket on the balcony but none in the living room or bedrooms with no earth pin or contacts in those sockets. Watch out for sockets on a switched lighting circuit. The balcony socket was in chain with the socket I wanted to use for the system and the earth wire was present as an unconnected loop so no major work was involved to connect it.
Our apartment in Montpellier (1970s build) had earth connected in the kitchen, bathroom (on a 32A socket for a washing machine) and to an outside socket on the balcony but none in the living room or bedrooms with no earth pin or contacts in those sockets. Watch out for sockets on a switched lighting circuit. The balcony socket was in chain with the socket I wanted to use for the system and the earth wire was present as an unconnected loop so no major work was involved to connect it.