My 16 year old DS has been invited to stay in the southwest of France with his friend and friend's mother (they are French). However, they are already there and he needs to travel down on his own. He has flown on his own before (which I have been ok with) but this time the only option is by Eurostar (no - cheap - flights available). This would involve changing trains in Paris - ie travelling by Metro between stations for connection. I feel a little uncomfortable with this - although he is fairly confident and is practising asking for directions in French... Any feelings on this - am I being over-cautious?