What is more tax efficient for services agreement structures, an SAS or an entreprise individuelle?

Hi Valerie

I hope you are well – a follow-up and updated questions to a previous thread, please. I have previously written that my husband (British/Canadian citizen) and I (French/British citizen) currently run an UK LLP selling research to global (corporate) clients, which is based out of London. The LLP is structured as 51% my husband, 49% myself. We have no employees and will primarily run the business from our home office in France. Our family has just moved to France permanently and my husband and I are taking steps to establish an incorporated French company since we will be French tax residents this year.

Based on advice you have given on the site and to us previously, we plan to operate two separate businesses: the current UK LLP detailed above and a new French registered business - each will have its own identity, accounts, etc. We need to keep the business in the UK for regulatory reasons and it is not feasible at this point to have customers switch from paying the UK LLP to paying the French company.

A few questions, please:

1. We are now considering either an SAS or an entreprise individuelle with regime reel simplifie - one each, for myself and my husband. Is there a reason why an EI might not be in our interest?
2. Which business structure works best if we expect reasonably high deductible expenses at the French company (i.e. working from home, flights to London)?
3. Are there any differences in the types of expenses that you can deduct at an SAS versus an EI?
4. My husband (research-focused) and I (marketing-, legal-focused) have very different roles at the company and can justify that our services rendered to the UK LLP keep that business running. Is a logical strategy for the SAS or EI to invoice the UK LLP for the work we do?
5. Are there any complications with this invoicing strategy and either company structure since my husband and I would only be working for one client (our UK LLP business)?
6. Since we are French tax residents, all net profits generated at the UK LLP will be liable to French income tax. We will declare these profits as our respective income earned abroad, in addition to any salaries or dividends paid by the SAS (or just income, in the case of an EI). As French tax payers, under this structure, can we take advantage of the international Double Tax treaties with regards to UK LLP net profits?
7. Expenses are high at our UK LLP so we would like to keep money in the UK rather than transferring a lot to our French company (understanding that we will pay French taxes on any UK LLP net profits). Through a services agreement (the invoices per #4), can we control and limit the amount charged by the French company to the UK LLP? Can we make this as small or as large as we would like?

Thank you