This looks great in its new widescreen version.
I felt that the movie dragged a bit at 100m, but it's definitely a worthwhile noir. The IMDb time says 83 minutes.
The locations are excellent. This time a causeway or road of 4 miles length is open to traffic at low tide, and otherwise flooded over. This creates certain neat and suspenseful story possibilities.
Vet Jean-Marc Bory is married to Liselotte Pulver, but he falls for Juliette Gréco and she for him. She lives on the island. She's been tutored in the black arts in Africa, whence arise the hexes. She lives in her decadent estate with maidservant Mathé Mansoura, after the death of her first husband. Also in the household is a lovely cheetah that Bory examines -- no fake shots or stand-ins either.
This is a very good Decoin movie in a psychological vein. You cannot go wrong with these French noirs.