From the name of Jacques de la Palice. His epitaph reads Ci gît Monſieur de La Palice: Si il' n'était pas mort, il ferait encore envie. "Here lies the lord of La Palice: If he weren't dead, he would still be envied." However, it was misread (accidentally or intentionally) as the truism ...il ſerait (serait) encore en vie, "...he would still be alive".
lapalissade f (plural lapalissades)