I am very surprised, even astonished that Susan has received permission to teach in France with (presumably?) a UK JAA FI.
I hold a French CPL/IR and was considering doing a UK FI. However, the French DGAC told me that it would not be recognised here in France and that if I wished to work as an instructor here I would have to do a French instructor rating.
I have a French friend here who has everything the other way round to me - he has UK CPL/IR and a French instructors rating, and he has no problem to work as an instructor in France.
The French are exceptionally obstructive about accepting qualifications from other JAA countries - they won't even accept my CAA FRTOL as evidence that I can speak English, and I have to go to Paris to have my English tested by a French examiner!