getting into the French health system

[needhelp]

If you live in France, but don't actually work in France (you work for an offshore company), is it possible to opt to pay a voluntary contribution in order to get health cover in the French system?

The reason I ask is that my company do not deduct either tax or NI, so my wage is gross and I want and NEED to pay into something in order to get cover.   I am trying to find out if there is a contribution I can pay in the UK which will give cover such as the E106 (mine expires next March).

This is all a very confusing issue, I don't work in France so haven't got a French employer but still need health cover somehow.