> Anecdotally, of my two EU (massive legacy French) banks, neither requires a mobile app. SMS all the way.
My wording was bad, sorry; but try to install their app just once. After that, I'd bet you won't ever be able to go back to SMS validation (which is what I was talking about at the end of my comment).
If not, I'd be curious to know the banks you're talking about (to consider switching to them, for one thing). What I said above is true of Caisse d'Epargne, HSBC, CCF, among others.
>I'd be curious to know the banks you're talking about
Fortuneo (internet-only subsidiary of Crédit Mutuel) and LCL. I have had both their apps installed at points in the past. In both cases they defaulted back to SMS 2FA upon uninstalling, though I remember worrying I would have the problem you describe.
Ultimately I can't see how a bank could get away with forcing (rather than just pushing) existing customers to install an app. This would surely be a breach of contract.