As others have pointed out there are few French speakers outside of Quebec, best to play it safe and have the IDP.

Also, if OP is renting from Hertz you can search for the specific location you're renting from on their website and it will show you the qualification requirements that are specific to that particular location. Looking at a few of the locations, I've rented from in the past they all indicate an IDP is required if the License is not in English or French.