The Mysterious Mansion

The Mysterious Mansion is a mystery novel by Maurice Leblanc featuring Arsène Lupin published in French first as a serial in June–July 1928 and as a book by Pierre Lafitte in July 1929.
A first English translation was published in New York by The Macaulay Co in 1930 as The Mélamare Mystery and a second one in 2014 by The Koch and Co Agency.

Summary

After the sensational theft of diamonds at the Paris Opera and the abduction of an actress, Régine Aubry, the jovial jewel magnate Van Houben has no choice but to use the services of gentleman-sailor Jean d'Enneris, aka Arsène Lupin, who joins his own rival Brigadier Béchoux. With a second kidnapping, that of pretty model Arlette Mazolle, the mystery thickens. Soon it leads to the hôtel particulier, or mansion, of Count de Mélamare, and d'Enneris uncovers a history of hatred between two rival families revolving around the mansion.