You can select the proiper options during the puirchase. Otehrwise simply call support. Yes, German support actually works (so unlike the defunct US support)...
I rather wanted to buy from a official german software reseller here in germany, not from adobe itself.
So there is just the offer number 65158519AD01A00 (also findable via google) for "Adobe Photoshop CS6 englisch Upgrade",
a TLP license for upgrading Photoshop CS5 or Photoshop Extended CS5.
If it is like the US be careful of resellers. There are lots of illegal software sold out there. If the price is too good to be true it is probably fake. When you get it call customer service to see if it is a valid copy if things don't seem right.
Well, I wouldn't say "too good", just some 15% or so cheaper than adobe, the usual list price versus market price divergence I think.
And some are official adobe resellers with thoroughly positive feedback in the local price checking sites.