score:8
Quite the same happened to me, but I was travelling with my wife (who does not share my family name but kept her maiden name). Her ticket however had my name printed. In summary: it worked out. But it was a little difficult. ;-)
Regarding your questions:
I would however suggest to contact them directly and explain the situation and get their opinion on the case.
Upvote:4
It's very much luck of the draw.
Technically the conductor can ask for ID and check your name against the ticket and see that it is invalid thus as good as travelling without a ticket; the fine for this could be up to 88 euros. https://www.thelocal.fr/20150220/sncf-to-increase-fines-for-ticket-dodgers
However I've never encountered a conductor in France who was bored enough/enough of a dick to do this. The majority of the time they will just check your ticket and not bother to check your name.
Even if they do check your IDs, with a small mistake like this any decent person would let it go. Again; technically the conductor could class the ticket as invalid but if you're nice with them and they're a decent person in a good mood they probably won't.
I guess it comes down to how much of a gambling man you are. Take account of your finances and compare the possible fine if you get unlucky to the cost of booking a 100% correct ticket.