Which is the best way to set up a geological consultancy in France?

I’m a geological consultant, working entirely outside France, but living in Le Lot. I have just returned from working for 18 months for an oil company in Houston and now I want to set up a consultancy business in France. Can you advise when and how this could be achieved? Before working in the USA, my wife and I ran an entreprise unipersonnelle à responsabilité limitée (EURL) business, here in France, also a geological consultancy.

I will have a visa for work in the USA as an occasional consultant associate to a company in Houston. I also have a US social security number and half of my tax for 2015 will be paid in the USA.

As far as I can see, there are several alternatives:

• To set up again in France as self-employed.
• To set up somewhere else in Europe, e.g. UK, in some form of legal entity.
• To work for the Houston based company full time, and any work carried out during periods not working for the US company could be invoiced through them and be subject to US tax. I have a tentative agreement with the US company to do that with a 5% to 10% charge payable to the company.
• To work on a mixed flexible basis. I think that the European work (based in France, but working in other European countries via the North Sea) will be a minor component of the total income. I could set up as a micro-enterprise in France, so that I could participate in the tax system of the company where I live, and then any work that would see me breaching the upper financial limit of the micro-enterprise could be invoiced via the USA.

Please could you give me some advise on the best possible way to proceed with starting the consultancy business here in France?