Send them a mail with screenshot from Europcar profile and received following answer:
I received your recent inquiry concerning your Hertz #1 Club Gold membership status.
The Hertz Status Match Program was established to match your current member status with Avis or National/Enterprise. However as a courtesy, I will go ahead with upgrading your status to Five Star since you are a frequent renter.
Normally we do not match Europcar.
Thanks for renting from Hertz.
on April 5, 2017