The Enchantress of Mayfair

Rich, ennobled men are dying across Mayfair.
It begins with a Duke's heir and soon the murder has trickled into Miss Christine Downing's life. She has only been married a matter of days before her husband's elder brother is found dead at the opera.
The Magisters, responsible for the regulation of magic in country, place the blame on Enchantresses, the female sorcerers. Though England does not recognize any official Enchantress, women are still able to practise their domestic arts.
Christine has long entertained hopes of being able to call herself an Enchantress one day. But, the murders in Mayfair dim that chance with each passing day.
The murders reek of a scandal that haunted the halls of Versailles years ago and Christine soon decides there answers lie in the past.