Hi Michele,
Did you import a CSV file using the Import / Export tool (Customize > Integration Tools)? I've been unable to reproduce this issue on my end, these French characters remained after I imported: àâéèëêî. Did you try with other characters? If so, can you paste some of these characters into this forum post so I can try on my end?
A find and replace could solve this but would take some work, so I'd like to investigate why the import didn't work for you.
Please let me know if you have any questions.
Regards,
Russell