You can collect email data in .mbox text files using a search engine. For example, a google search for filetype:mbox from
results in plenty of .mbox data. My best attempt at French-only .mbox files is this search.
Individual .mbox files can be concatenated into one large file (linux method):
cat mboxfile1 > mboxfile
echo >> mboxfile
cat mboxfile2 >> mboxfile
To parse the text, one option is the mailbox library in python. See an example code here. Here is the important snippet
import mailbox
mbox = mailbox.mbox('emails.mbox')
for message in mbox:
print str(message.get_payload()) # print body of each email in emails.mbox file
(my self-sourcemy self-source)
Along this line you can also look for French language chat logs (i.e. IRC logs)