I don't know if it's the same in Word97 - I've got Word2000 and there is a French (and Spanish)dictionaly included with the English version.
If you install Office, or just Word in French, there are ceratin common, but different, language files, and you will end up with a terrible mishmash - I know, I've tried with English and Spanish versions. It can work better with WinXP if you set up two users, one in English, one in Spanish - but earlier Windows will be a diaster.
I'm not sure about just the dictionary files, and sorr,y but don'e have time to look right now. Try the MicroSoft site.