It costs the same as in the US, but in pounds or euro not dollars.
In the US coffee costs between $1 and $5.
Same in London and Paris.
But no, you rarely if ever get free refills.

Besides, the coffee you'll be served in Paris probably does not correspond to you idea of coffee.

Think of short shots of espresso coffee from Starbucks and that's the kind of coffee you'll get in Paris. There's no such thing as refills.

free refills of anything is an anaethema to modern humanity. Stop the free refill now !!!

My morning latte from the local Costa Coffee is £1.89. Other coffee chains cost about the same.
In Paris, you pay less for coffee if you stand at the counter than if you sit at a table. You pay less if you pick an "ordinary" cafe versus someplace more fashionable. You also pay less if you get a cup of coffee at your local patisserie/boulangerie (if they happen to serve it).
I don't drink straight espresso. Don't like it. So what I pay for my cafe creme (similar to or the same as a cappuccino, depending on where you get it), I pay anywhere from 1.5€ standing at the counter at a cafe like the Royal Mozart to 5€ for sitting at the table at Scossa, a trendy spot on the Place Victor Hugo.

I buy a Pret a Manger latte every morning on the way to work. Costs £1.69. There are a few places dotted around that do refills but they tend to be American diner-style restaurants. I wouldn't want it anyway. It's swill.

I remember my first "cup of coffee" on an Italian Eurostar train..actually my first cup of coffee anywhere in Italy.

At first I thought the cup had cup from Toys-R-Us it was that big. Then I looked WAAAAAAAAAAY down to the bottom looking for the coffee..it was there...this tiny little pool of dark stuff which just barely seemed to reach the sides of the cup...

hmmmmm....was it fun? Of course but took a little getting used to.

You don't get free refills in Europe but the coffee is much stronger and you usually have to pay to use the toilet in Europe. If they gave you free refills, you would have to cut your trip to Europe short because you would be out of money "paying to use the toilet."

If you are in France, I would skip the coffee and go straight for the wine. It is cheaper--much cheaper.

Absolutely! My splurge is 1/2 bottle Chateau d'Yquem with petit dejeuner but if I am not feeling flush I just go for a nice Vouvray half-bottle.

Please, cost at McDonald's in London and in Paris? Toilet charge?

Naaaaawgh!!!!!!!! Don't go to the Golden Arches! Not in Paris surely?

Apparently my wife and I -- who thought we had been going to Europe (including the UK, London and Paris) yearly for the past 12 years -- have really been going somewhere else. I agree with Neopolitan that prices in Europe and UK are roughly the same in euros and pounds as in dollars in the US. However, for "ordinary" coffee we have found many places that will give refills, if asked. I would not expect refills on "special" coffees, such as espresso, cappuccion or latte, in the US or in Europe. And, our recent experience is that in ordinary cafes, restaurants or department stores, there is rarely a toilet attendant, and no charge -- similar to most places in the US. McD's in London will be about the same amount in pounds that you would pay in dollars in the US -- so, maybe 80% higher on a dollar basis -- but not much more than in some captive markets in the US.