Tell me what to do if the scammer registered a domain with the .eth?
In more detail, the domain in the DNS zone is quite well known and an international trademark is registered on it. How to return the rights to a domain with the .eth extension?
Nothing ENS can do in this case. Centralised marketplaces can blacklist them if they are served with DMCA on behalf of domain.com in question. Other than that, nothing ENS can do.