Who do I declare agent commercial declarations to?

I have a chambres d’hôte in France and am registered as an auto entrepreneur business. Last year, I registered also as an agent commercial (I have all my registration docs from the chambre de commerce), working in conjunction with an estate agency. I didn’t really think about where I should declare any income, but I assumed I would just declare with RSI, but am having doubts having tried to find out on the internet.

1. I have just earned my first commission, and am not sure if I can (or should) declare my income with Régime Social des Indépendants (RSI) as I do for the chambres d’hôte, or if I should declare to Unions de Recouvrement des Cotisations de Sécurité Sociale et d’Allocations Familiales (URSSAF) instead?
2. If I do declare with RSI, which bracket does agent commercial income come under?
3. I think for the chambres d’hôte, on the declaration des revenus form, I put my income under ventes de marchandises. Which line on the form (percentage) is applicable to agent commercial - ventes de marchandises or prestations de service?
4. The other thing I’m concerned about is if I declare both incomes as auto entrepreneur. If I earn a large commission as an agent commercial and it takes me over the turnover for auto entrepreneur, does this mean I can no longer be an auto entrepreneur for the chambres d’hotes too, even if the chambres d’hôte part of the income doesn’t go over the limit?