It is apparent from the circumstances which are known - travelling to France - that this couple have not put any serious coherent thought into their actions.
If they are in a committed relationship and plan to be togehter, then taking a child abroad without parental consent and taking leave of absence from his teaching post are not the way to proceed.
The couple may well have been carried away on an emotional wave with the attendant daring and romance of going away together, but as the emotional impact ebbs and the practical considerations increase, it will dawn on them that they have to come home - and they will because they will have no choice.
Love does not live on fresh air - they need fuel, food, accomodation, income, and a plan for the future, and indications are they have few, if any of these essentials.
As to charges and so on, that will have to wait until the full circumstances are known, but this foolish man has certainly lost his career, and possibly his marriage through his actions, which do not indicate the workings of a mature and adult mind.