French searchers are lazy spellers..

é - è - ê or plain e?

[vitaplease]

[revue-referencement.com...]

On average only 47% of the search query words are typed with a correct accent.

Female words tend to spelled correctly more often ;)

BTW, Google does generally not offer the correct suggestion if you misspell.

[Macguru]

I use to work on many French language sites. My numbers match the study for broad public oriented sites (consumers sites).

I believe the main factor is computer related. Either these people purchased a English keybord or dont know how to set it up to type accentuated caracters.

The second factor is they dont know what the SE they are using do with special caracters. So they do without.

I tell my clients about this and leave them to decide if they want a few special pages to meet this demand.

[heini]

Another workaround is to use keywords in filenames. Urls don't allow for non ASCII characters, therefore you'll have them in there without accents.
Also a good place to stuff alternative spellings are alt txts etc

[Macguru]

Some of those misspels (did I spell is right?) are in too high competition to get a decent ranking with filenames and alt tag alone. I really need to expand the typo to other visible spots of page to beat competition.

Now dont shoot me, while not correct, it is more acceptable to use non accentuated versions in ALL CAPS. I have a couple of page titles like that...

We usually built a "side version" of site for misspels. Nav buttons are linking to pages with correct spelling. And for a couple of clients who can't afford to have any pages with misspels in public, we use a special script...

Sidenote : I sometimes see some correctly spelled pages in SERPs called by misspels for freshly crawled pages on Google.

I will use a phony example : Fresh page "L'Académie de la Langue Française" will be on top for the "L'Academie de la Langue Francaise" query, in the 'fresh' month.

[Rumbas]

Mispellings.
A good trick; if your site can 'handle it' is to make a page with all the mispellings you find in the log. On this page you list the misspellings that people have found your site on and maybe make a paragraph or two about it.

Totally valid and can be a good laugh for your visitors.