She would only need a RIO code if she intended to switch mobile providers in France and keep her phone number. A brand new SIM would not need it. Instead she'd just be assigned a new phone number.

It's a thing specific to France to facilitate seamless switching between providers similar to our phone number portability here in Canada.

If her phone supports eSIM (most iPhones since 2019 do) she can also download one of the many eSIM apps and get data that way. These eSIMs usually never come with voice capabilities, just data, if that is a concern.

Since you cannot port your Canadian koodo number to a France carrier, there is no need for an RIO code. 

You just need to sign up as a new pay-as-you-go customer