A hatter in a provincial town (Michel Serrault) leads the life of a respectable citizen but is in fact a serial murderer. The only person to suspect this is his neighbour the tailor (Charles Asnavour).
| Directing | Claude Chabrol | Director |
| Writing | Claude Chabrol | Writer |
| Writing | Georges Simenon | Novel |
| Sound | Matthieu Chabrol | Original Music Composer |
| Camera | Jean Rabier | Director of Photography |
| Editing | Monique Fardoulis | Editor |
