French dictionary, “classic” spelling is a Thunderbird extension that contains only the classic spelling of words.
If you consider that “maitre”, “relai”, “cout”, “évènement”, “connaitre”, “assoir”, “contrindiquer”, “bassefosse”, “révolver”, “règlementaire”, “j'amoncèle”, “aigüe” . . . are spelling mistakes, this is the dictionary you should use.
About the French spelling reform of 1990: Wikipedia
Note: If you do not know what dictionary to choose, select "Classic & reform 1990" dictionary, as the classic and new spelling of words changed by the reform are both correct in French.
For Hunspell, spellchecker of Firefox 3, Thunderbird 3 and Seamonkey 2.
How to Install in Thunderbird:
1. Right-click the link below and choose "Save Link As..." to download and save the file to your hard disk.
2. In Mozilla Thunderbird, open Add-ons from the Tools menu.
3. Click the Install button, and locate/select the file you downloaded and click "OK".
Product's homepage
Requirements:
· Mozilla Thunderbird
What's New in This Release: [ read full changelog ]
· Bug fixes in the affixes file.