I'm currently in France for 3 months from Perth at an AirBnB. In Australia I have an Aldi plan which uses the Telstra network. Before leaving Australia I downloaded the Truphone ESim and then activated the plan when I landed at CDG. The cost is $AUD25 for 10gb/30days and I have auto-renewal turned on. Global roaming is enabled on my AU number but will use it only in an emergency. It also may be useful should I need to receive an SMS to verify security when logging into certain sites (ie MyGov) or to validate the occasional unusual debit card VISA transaction.
My AirBnB includes WiFi so I really only need the data plan when I'm out and about. Using Facebook Messenger or SKYPE to video chat/phone friends & family in AU and US. I travelled to the US back in March using this same methodology without any issues. The amount of my global roaming charges for a 3-week trip away was about $2, For me, that is a lot easier than swapping SIMs in and out. Most newer model phones should have no issues accepting an ESim and you have the flexibility of controlling via settings which sim to use. You can run them concurrently or turn one on/off as required.
I will only be in France this trip but I believe Truphone also offers plans that work in multiple European countries. Just a thought to consider.