I have many TLD's for my domain, for US users it's .COM, for German users it's .DE, etc. I redirect them all to the .COM domain using CNAME records. The reason is to prevent getting a penalty from Google for duplicate content.
Is there a way to still detect the TLD the user entered, so I can display the page in the right language?
If you use CNAME records, google will still regard the sites as different domains, and will penalize them for duplicate content.
You should redirect your users with a HTTP 301 response. When you do this, you can also add a query string when redirecting:
www.example.de -> www.example.com/?lang=de
This way, you won't be penalized for duplicate content, and you can detect your user's language.
