"There are many rabbis in my family. It's a dynasty. I'm very attached to that tradition - we celebrate the rabbis, what they have done, their miracles and wisdom," she says.
An artistic leaning was never encouraged. Not in Morocco, nor later in France where the family moved to escape rising tension between the Jewish community and its neighbours. "We never had big problems. But we went away because it was tense, and because for education it was better to be in France."
Her father ran a transportation company in Morocco, then transferred his business to French hypermarkets. The young Karen obligingly took her business studies seriously, but she had a habit of indulging her dance hobby.
"Nobody was an artist in my family. But I was always taking dance and singing classes. I was very artistic inside, but it was hard to express that in the family context."
No one, least of all Ruimy, could have predicted that this hobby would become her profession. "I was managing a brokerage company, and I just decided: ‘That's it!' I had no heart for it, my heart was in the art. I dedicated myself to dancing, singing and writing. About seven years ago I started to build projects with flamenco, my main passion."
With the chutzpah of a true amateur, Ruimy instantly turned professional. She worked with her teachers to make a flamenco show that would be suited to a large theatre, rather than the traditional Andalucian intimate setting.
Theatre de Paris took the show, 15 dancers and seven musicians were recruited, and Ruimy found herself with a hit formula on her hands.
"Traditional flamenco is usually in small venues, for aficionados. I wanted to create bigger shows for bigger audiences, to show the soul of flamenco and at the same time have fun." Performances sold out, and the company was inundated with requests for classes.
The unstoppable Ruimy has expanded and refined her shows ever since, adding different musical genres, making links with tango, and filling some of the most prestigious venues in Paris - including the legendary Folies Bergère.
The UK show features many of the same elements, including the cast, but has a new director - Craig Revel Horwood, the abrasive judge on the hit TV show Strictly Come Dancing.
They have taken inspiration from the fiction of Argentine writer Jorge Luis Borges. Street knife-fights and love triangles with deadly consequences are the kind of narrative ingredients that Ruimy and Horwood agree suit the language of flamenco, although Ruimy is keen to draw attention away from the need for storylines.
"It's less about story, and more about seeing someone express their art. Women can express strength. Men can express sensuality and stay masculine."
How easy was it for someone of her Jewish upbringing to become versed in the form?
"Flamenco was created by experience. It is not a luxury. It is the expression of a people who were obliged to travel from East to West. Very rarely will you find in an art that level of passion, of expressing your guts."
If that story of migration sounds similar to the Jewish one, the music takes the parallels even further.
"When I hear some of the singing, I think I am in a synagogue. They took in all the influences of Europe - especially Arabic music and Jewish singing," she says. "Anyone who is close to a tradition - be it Jewish, Arabic or Mediterranean - is absolutely touched by this music, because it's history talking."
Flamenco Flamen'ka is at the Lyric Theatre, London W6 for eight weeks. www.flamencoflamenka.com
Ruimy was born in Morocco, and traditional education was an important element of her upbringing. Her great uncle was the venerated Rabbi Israel Abehassera.