I mailed back, seeking additional intelligence:

Haha! Thank you very much for telling me how to get into the country!
This information will be most useful to us. With this "visa" we
shall easily enter France undetected.

Do you know if there are any secret tunnels that lead under Paris?
What about the sewer system?

Your loyalty will be greatly rewarded, Frenchman. Once conquest is
complete, you shall be appointed to a position of your own choosing.

Keep in touch. We may need you to act as translator once we have
infiltrated the country