You're linking a source that you don't understand. "Toute personne qui refuse délibérément de s’affilier ou qui demande à ne plus être affiliée à un régime de sécurité sociale"
This has nothing to do with freedom of speech.
And since when is it illegal to talk about homosexuals, non-white people or jews ?
That's false. The government of France never tried to pass such a bill. It was a mayor of a small town that tried to ban burkinis but this bill was suspended by a higher court.
You can start testing your ideas working as an auto-entrepreneur on your personal websites or mobile apps and later create a startup when you need funding.