All I can say is: this thing is great!

Hi Franco, then send the stove back - 14 days right of return for online purchases ... Even the buttons are labelled in German ... Good luck!

Here are the instructions for use in French: https://dlc.panasonic-europe-service.com/EUDocs...

I also have this problem and the solution suggested below doesn't work: after unplugging, the display doesn't show "88:88*" but German text.
Would it be possible to access the detailed instructions? My French (user) manual has NO p 68...

According to the instructions on page 65:
Disconnect the appliance plug from the mains socket for a few seconds and then reconnect the appliance to the mains.
power supply. When "88:88" is displayed, touch Start repeatedly until your language appears.
Then set the time.

The same, only in German