A historian seeks to clarify the mysterious death of Sire de Malvaleix and will find himself involved in the murder of the current descendant.
| Actor | Role |
|---|---|
 Henri AriusNot listed | Not listed |
| JJules BerryProfessor Barbaroux | Professor Barbaroux |
| PPauline CartonMadame Barbaroux | Madame Barbaroux |
 Chukry-BeyNot listed | Not listed |
 Francis ClaudeNot listed | Not listed |
| YYvonne DucosNot listed | Not listed |
| LLucie DupleixMadame de Hennebelle | Madame de Hennebelle |
| AAlexandre FédoNot listed | Not listed |
| YYana GaniNot listed | Not listed |
 Vanda GrévilleNot listed | Not listed |
 Jim GéraldCommissioner Plachon | Commissioner Plachon |
 Philippe HersentGérard | Gérard |
| JJean HeuzéThe Lieutenant of the Gendarmerie | The Lieutenant of the Gendarmerie |
| RRoger HédouinMarquis | Marquis |
| PPhilippe JanvierNot listed | Not listed |
| CCharles LavialleNot listed | Not listed |
| GGéo LecomteNot listed | Not listed |
| PPaul MasqueNot listed | Not listed |
 Milly MathisThe cook | The cook |
 Simone ParisMona Lambelle | Mona Lambelle |
| GGisèle ParryChristine | Christine |
| PPierre PasseronNot listed | Not listed |
 Pierre StéphenOrfray | Orfray |
 Jacques TarrideThe valet | The valet |