For readers in Britain, you may have more details on this case than I do, and that fortunately is not the question. It is a case between a married 30 year old teacher and his 15 year old student who had a crush on him and from what I gather from the report exchanged explicit texts, went to France where they were on the run for a few days. I gather the teacher is being accused of abduction.
The question here is, when is a girl/boy mature enough to consent to sex? Though the teacher isn’t on trial for any sex offence as far as I can tell, I think this relationship between the two of them forms a good basis for dealing with the question of consensual sex.
Random thoughts 