Although the French famously have no word for 'entrepreneur' they have just launched a new tax regime that is worth mentioning if you're thinking of setting up a business in France.
The Auto-entrepreneur scheme allows you to set up your business as a 'micro-enterprise' providing trade, crafts or services as either a main or background (secondary) business. As long as your turnover doesn't exceed €32,000 for services and €80,000 for trading you can register as an auto-entrepreneur. If your turnover does exceed these limits you'll need to become VAT registered and possibly register your business under a different regime. However, it still might be a good place to start.
The main advantage of the Auto-entrepreneur scheme is that you can pay your social charges (cotisations) depending upon your actual turnover either monthly or quarterly. Other tax regimes can require you to pay these upfront. Income tax can also be paid in accordance with your turnover.
You can register online for the regime and a lot more information, including getting started guides can be found on the 'auto-entrepreneur' website.
If you're living/working in France and are already registered as an 'entreprise individuelle' it doesn't appear that you can switch to the auto-entrepreneur status, however you can still get some of the benefits by switching to the Régime "micro social" which will allow you to pay your social charges in line with your turnover either monthly or quarterly.
