Hi Georgeanne,
The school you have been hired to teach at may be owned by French but it is in your country, your state. I don't believe giving everyone a gift and then writing a note in French would be appropriate at this time. It's message may be misconstrued as "trying too hard to fit in". Doing your job well and just being yourself will speak volumes to everyone. Then, as time goes on, you may want to learn their language as they have learned ours. Good luck to you!
neecigirl