I always watched 'Allo 'Allo years ago and although I don't find the series as funny now, I always remember the scene where Lieutenant Gruber and Helga visit Nouvion in the then present day at the end of the last episode. I remember René's son being at the cafe (he was played by Gorden Kaye as well) and when they meet René again (who is very old and in a wheelchair) he tells then that the son was "an orphaned baby, left on the doorstep, I told him that I was his father".
Something I don't get is when René tells this to Gruber and Helga, the audience roars with laughter. Am I missing a joke here? I also remember Colonel Von Strohm being Gruber and Helga's chauffeur - but wouldn't he have been too old? By looking at the last scene and the style of Gruber's Mercedes, it looks exactly like the then present day of 1992 - but wasn't the Colonel meant to be much older than René during the war?