Hi florentin77,
Thanks for posting in Apple Support Communities! Since your Apple TV seems to be stuck during setup, follow the guidance below from the article Set up your Apple TV to get your device working again:
"If your Apple TV stops responding during setup, unplug your Apple TV from power, then plug it back in.
If you can't get past a screen during setup, try connecting your Apple TV to a different Wi-Fi network, like a personal hotspot from your phone. After setup is complete, go to Settings on your Apple TV and connect to your home Wi-Fi network."
If the behavior continues, contact Apple Support.
Cheers!