Hi Fiona,
I'm a qualified FLE teacher ( Français Langue Etrangère) if it can help. I've lived here for the past 3 years and I teach English to student nurses but I used to teach French at the University of Antilles Guyane just before that.
As for a language school for French language,I haven't had the opportunity to look around for one.
Don't hesitate to get in touch if you don't manage to find a school, I'll be pleased to help.
Nicole