What is the best way to set up our gite rental business in France

We need clarification on best way to set up our gite rental business and reduce our social and tax as much as possible. We will rent out our farmhouse from 1st April 2015 to UK holidaymakers.

• We are not married and own 50% each of the property each and run the business together.
• We have no mortgage on the property.
• We are likely to earn a maximum of around 15,000 euros per year between us from the rental.
• We also will host French students in our house (not the rental property) and they will receive English lessons. We provide food, activities and bed for them. They come for a week at a time through a French agency. This income will be about 5,000 euros per year.
• We will share the income after costs between us equally.
• Our total direct costs for running the business would be around 5,000 euros.

We estimate a total income of around 20,000 euros, i.e. 25% hosting for English lessons and 75% farmhouse rental. This is our only income at the moment.

1. Is the hosting for English lessons in our house treated differently to renting the farmhouse for tax and social charges as we are offering the students far more than just accommodation?
2. As we are not married, own 50% each of house and running the business as our sole source of income as a partnership is there a way to set up so we both get our tax relief and reduce any social charges?
3. I read on your posts somewhere that auto-entrepreneurs don’t pay social charges in their first 2 years or was it a nice dream?
4. Do we have to register with the Chamber of Commerce?
5. Given the above is the best way to set up our business in France?