Hibernatus

In this 1969 French-Italian comedy film, Louis de Funès stars as Hubert de Tartas, an industrialist whose life becomes a muddle when his wife's grandfather, Bernard Alane, is thawed out after 65 years in hibernation. To keep the old man's identity as a 90-year-old young man from being revealed, Hubert must play along and pretend to be courting his wife Claude Gensac, while also navigating his own marriage and family dynamics with his son Olivier de Funès. The situation gradually deteriorates as Paul Fournier, aka "Hibernatus," becomes increasingly confused about his surroundings.