Ok, now it’s more clear.
For the error: set_time_limit()
You have to modify php.ini file and set set_time_limit() to -1 Or contact the hosting to increase your limit. That error comes from Hosting (a limit set by them to prevent you from using too many resources). And that page needs more resources.
For “Toute durée”, we recently added a solution for German characters in Titles and slugs (i think will work for French as well). The solution was tested with German characters succesffuly. I can email you the files you need to update (but you’ll need first to update to v2.03). Can you please post here your email address? To send you these files?
http://www.la4emedimension.org/espace-cev/locations/ – is also related to French cgaracters (and how WordPress saves them). The above work for this as well, if it works for Advanced Search.