The Devil's Possessed (1974) on Netflix

Plot summary

The Baron Gilles de Lancre gives himself over to alchemy and black magic, and his wife Georgelle encourages the interest. He wants to expand his power and reach the royal throne. She leads him to believe that her friend Simon de Braqueville, an alchemist, can change lead into gold, given a quantity of virgins' blood. His soldiers seize young virgins from the area, and Georgelle has the girls sacrificed. Gaston de Malebranche, an old friend of the Baron and a captain in his army who has been away on a long journey, hears strange accounts of the Baron and his household.