Made a mistake in TGV tickets booking HELP
 

I bought 4 tickets Paris-Marseille for my family of 3 adults and 1 child. But I mixed up and entered my husband's details (name, date of birth) under child's ticket and my child's name and date of birth under an adult's ticket. the other 2adult tickets are completely correct.
I am looking for advice on this. If we turn up with these tickets, will they let us on the train?
And do they check tickets before you get on the train or after?
All passenger details are correct, and we are still 3 adults and 1 child like the 3 adult and 1 child tickets we bought.

There are no more tickets for the same date for the same price left (only more expensive ones) and I'd rather not change anything.

thank you for your informed advice!!

The conductor will pass and check you tickets on the train after the departure. No worry.

I would be ready to explain the mix up of birth dates to the conductor if asked but woud not be worried either.

Only the iDTGV trains check and confirm ticketing before boarding. Otherwise there will most likely be a conductor who passes through the cars to check tickets.

As this is only a clerical error and not one of deception, I should not worry about it. You paid for 3 adults and 1 child and have been issued tickets accordingly. If you are asked why your husband is traveling with a childs ticket, simply show that the names were switched when the reservation was made.

> I would be ready to explain the mix up of birth dates to the conductor

With the passports (with bith dates of the two) ready so the conductor can see the mistake. Again if only asked.

Agree with kappa. You've paid the correct amount, just reversed names. The conductor WILL check your tickets, so you may have to explain (in French, no doubt).

> Only the iDTGV trains check and confirm ticketing before boarding.

Oh I didn't know that (never bought iDTGV tickets that don't run on the routes I travel). Thanks for info.

Thank you so much guys, you are awesome! I am relieved! Here in Ireland, it certainly would be 'just grand', no problem, especially because it isn't a serious mistake.
But I wasn't sure about France:)