On par with "The Devil Rides Out"?
This was made by Planet Film Productions, a minor rival of Hammer, and therefore has that Hammer horror vibe, along with Amicus and American International horror flicks of that era. It’s basically a vampire cult movie mixed with satanism and was the obvious inspiration of Hammer’s “The Devil Rides Out” (a.k.a. “The Devil's Bride”) (1968) and is at least on par with that more popular picture.
The story is set-up by a spirited gypsy sequence and turns mundane with Paul (William Sylvester) on holiday in Brittany. But things perk up at the mid-point with an unexpected beatnik party where an unanticipated side of the seemingly wholesome Madeleine (Diana Decker) is revealed. The party involves drinking, pot and corresponding debaucheries, albeit a little muted compared to what would be shown in the next few years, e.g. “The Wild Angels," “Easy Rider” and “Beyond the Valley of the Dolls." Nevertheless, this sequence perks up the movie.
The obedient chants of the goat-sucking buffoons are amusing, but the satantic rituals are well done and surprising for a film shot in 1964. It’s also interesting to see who’s a part of the secret cult. Fans of 60’s vampire/satanism flicks are encouraged to give this minor production a look. It’s worth catching simply as a historical peek into English/French culture of 1964.