The perfmon counters that are used are the US/English versions. Your french environment has french language counters. As a result, it won't work for performance metrics.
You have two choices:
Either one will work. You may engage our professional services team to do the adjustments if you do not feel you can do them yourself.
I did not find this performance counter is searching for English exchange counters. I do not see the raprochement performance counters with the research.
the beginning of the research begins with EventType:
eventtype=msexchange-index sourcetype=MSWindows::IIS cs_uri_stem="/EWS/" NOT (cs_username="\$" OR cs_username="-")