Carolina: UK and USA DNA testing is legal but France since 1994 have made it illegal and heavy fines are levied if found out.
France has some rigid succession laws, and a woman's husband is assumed to be the father of her children. The moratorium on DNA testing comes from a bioethics ruling in 1994. Paternity testing is illegal in France unless ordered by a court, and DNA testing is seen to be a form of this.
Personal DNA testing carries high fines in France. If a result was 'favourable' and could be made use of, then one would have to explain how the information came to light. Testing kits found by random customs checking can cause quite a bit of grief for the intended recipient.
I have seen a number of 'arguments' in favour of allowing it, with various qualities of discussion. All the ones I have looked at have been traceable to businesses that want to profit from it.
This doesn't help those who simply want to establish a general lineage, such as "Do I have a bit of country X ?" but there it is, cultural differences.
Andrew.