in Word Online, when you click on Paste, Einfügen in German, and the browser is not allowed to access the clipboard, you'll get an error message. In Chrome (only tested there), this message looks like the following screenshot.
In this dialog, the shortcuts are not translated. Ctrl should be translated to Strg. Additionally, the word also is not needed, as it's not a good wording in this case. Therefore, Verwenden Sie diese Tastenkombinationen: is ok.
Note: I noticed, that the German Version seems to only provide a single button for pasting, while Word Online English has a dropdown including an additional button for pasting as text only. I used Chrome as browser for the German version and the IE for the English version and did not reverse the test.