IPTV is actually pretty mature in France, my line is non-dégroupé so I’m “stuck” with Orange (actually the service has been OK) - basically you get the Livebox which is the modem/router/WiFi AP and a separate TV set-top box and remote control, you just hook that to the TV via HDMI and the Livebox (if memory serves that can be via Ethernet or WiFi). Originally I only went for the TV package because you can’t get VDSL without it - the service is free but the TV box adds to the rental, I think it’s 3€ a month.
It works just like any set-top box, has an EPG and with the higher packages wideo on demand etc. Bouygues, SFR, La Poste and Free all do TV packages and I imagine that the presentation is the same. Apparently more people now watch TV in France this way than via terrestrial broadcasting.
If you want UK or USA TV there are various options, usually with their own “box” or, if you are technically minded you could look at things like kodi to roll your own.
The technology involved is usually a VPN (Virtual Private Network) to make your IP connection appear to be coming from the UK and sometimes DNS tweaks to make access via the VPN transparent.
One potential limitation to these systems is that the UK broadcasters don’t really want you watching UK TV outside the UK so sometimes block the UK side of any VPN in use - it’s a bit of a game of whack a mole but occasionally you might find a service stops working. Also not all suppliers are legit - the police shut down a big pirate IPTV provider earlier this year.
Google something like “IPTV provider” or “IPTV provider France” if you are interested.