Converter or adapter for cell phone in England and France?

You only need a plug adaptor, two round pins for
France. The U.K. adaptor is different. Rick Steves' store sell them or go to a luggage store.

Go to the luggage section of any discount or department store. You will see a selection of adapters. I like mine which has 4 USB ports and a selection of correct "plug ins" for the various types of outlets around the world.

Look at these adapters from Amazon. I have the PowerAdd. 2 outlets, 2 USB ports plus a mini-USB and options to use it in the UK, Europe, Australia, Japan - even for charging devices in the US when your hotel has limited outlets. For dual electric devices, like chargers, you only need an adapter, not a converter.

My husband and I just got back from a trip to the UK and to Copenhagen, Stockholm and Norway. This Ceptics brand purchased on Amazon was recommended on this travel forum. I used the first linked one in the UK and another in the 3 Scandinavian countries we visited. I loved having the options this device provided, since I could use the two USB outlets for my iPhone, IPad Mini 4 and the outlet for my Apple watch. The second Ceptics was for the Scandinavian countries and most of Europe. This meant I only needed to bring the USB plugs for the first two listed devices. The Apple watch just went into the outlet on the Ceptics. Both performed beautifully for my use. I didn't bring a hair dryer or other hair styling devices relying instead on air dry or hair dryers in our hotel, Bed and Breakfast and Airbnbs.

If you don't look at the specifications plate on your phone chargers and camera you won't know and you could burn them up if they are not rated 100-250vac 50/60Hz.