The 51-year-old actor is shooting for "The Monuments Men" in Berlin and went for dinner with a few friends.
A nearby diner in the same restaurant, Oliver Hermann, then asked for his cheque, only to be informed by the waiter that Clooney had paid his USD 136 bill already, reported Femalefirst online.
Hermann said the waiter explained that the actor feared he and his party had disturbed him as they were too loud, so opted to pay for the meal on his behalf by way of apology.
Hermann, who had not recognised Clooney said, "That's not true at all (that Clooney was loud). They had behaved in a very cultivated manner. I was stunned."