Obligation de Qualification for personal fitness trainer in France?

I would like to start my own business as a personal fitness trainer in France. I already do private and semi-private (3 clients maximum) sessions in my home and in my clients’ homes. Clients buy packages of 3-9 one-hour sessions. In the near future I plan to offer an outdoor fitness class once a week (open to up to 8 people, meeting in a local park) where clients pay on site per class (or purchase 10 classes at a reduced price).

Sounds like auto-entrepreneur would be a good option for me, although perhaps I would be considered a profession liberale and need to wait for the new legislation to be passed? I don’t think I will declare my business until this fall as I expect my activity will be very minimal this summer so this shouldn’t be a problem for me.

My larger question is how do I know if I need a special diploma to practice my activity? In the US I do have proper certification, but here sports and fitness laws are so vague I don’t even know where to look to see if I am qualified. What would I call my profession in French? Is there even a code or category? When French friends ask what I do I say je fais du coaching personnel en remise en forme but this doesn’t really seem to mean much since personal fitness trainers don’t really exist in France. A preparateur physique is more or less equivalent but they never work independently, they are usually work either in gyms or are hired by sports clubs (both professional and amateur) to train the athletes. And I don’t know what training is required to call oneself a preparateur physique. Any ideas on where I could find this information?