What are telephone ethics in the UK and France?

This has to do with who drops the phone last after a conversation and how you answer the phone once you pick up the receiver.
Thanks

I'm French and my mom was always really strict about phone etiquette. She always said treat everyone with respect, when calling someones home there are no receptionist so I'd call my friends house and say "Hi. This is Lola, how are you?" I'd talk to my friends parents or siblings for a moment. At the very least I'd say "Good Evening. This is Lola, may I please speak to Sophie?"
And my mom required the same thing out of my friends who would call my house. She'd give them one warning if they said "Is Sophie there?" She'd politely tell them that she was not my receptionist and asked them to introduce themselves on the phone when they called. (None of my friends minded and actually still do it to me to this day!)
When picking up the phone a simple "allo!" would do, or good morning , good evening... that kind of thing.
I don't remember anything about hanging up that was out of the ordinary.
Hope that helps!

In the UK, it's the same as the US. It doesn't matter, you pick up as soon as you can and when you hang up, you both say a mutual goodbye.

they are the same in both countries

The only difference I know is, that in England we do not always say our name, we say hello !! or the number, as in France they always answer with there family name

It depends- Professional or casual phone calls.
At home i answer the phone by saying hello and i drop it last if he/she says bye first
At work i answer the phone by stating my name and the name of the company and end it by saying thank you and i let them drop the phone last.
That is in the uk

As far as i see across the globe the best thing to do when answering the phone is to say "Hello" and when the conversation is completed say "Goodbye".