What does French surname RENAUD mean?
Neither. Renaud is a French male personal name of Germanic origin, as Maxi says; it's the equivalent of English Reginald/Reynold and Scottish Ronald/Ranald. So as a surname it meant 'son of Renaud'. Lisa has it the wrong way round. Renaud (or 'Reynard' in England) was a personal name given to the fox, just as the wren was traditionally called 'Jenny Wren', the male cat was 'Tom Cat', the male donkey was 'Jack ***', the redbreast was 'Robin Redbreast' and the goat couple were 'Billy and Nanny (= Anne) Goat'. And this nickname for the fox eventually became the everyday word in French, just as 'robin' (originally a pet-form of 'Robert') is now the everyday word in English for the red-breasted thrush. According to behindthename, it's the 92nd commonest surname in France. So, while it's not stunningly common. it's a perfectly standard name.
Renaud surname comes from a Germanic personal name composed of the elements "ragin," meaning "counsel," and "wald," meaning "rule."
No. It is an animal name. It means Fox.