Hi, I live in France permanently, but I am of state pension age. There are various sites including Angloinfo that give full details of healthcare here but basically you get into the French Healthcare system and then you should get what is called a Mutuelle which is a top-up health insurance. There are various companies who provide different types of cover at different rates. I get my prescriptions including metformin and, whilst I am not absolutely sure, I think the system here will provide such prescriptions free of charge (always providing you have the Mutuelle which you should not be without) even if you are not of retirement age. There is an agreement between Governments which gives reciprocal arrangements in relation to Healthcare
I have found the healthcare in France particularly good if bureaucratic
Bon courage