Disclaimer: I am not Paris’ biggest fan. In fact it is my least favourite part of France.
That being said, there are the inevitable tourist sights to see in Paris, and like all major European cities, must be seen at least once. You could easily kill 2-3 days there and then get the Eurostar to central London.
Other info requested: Are you flying home from Paris? How are you getting to the UK?
Some of my favourite places in France:
- Quiberon (Brittany), pretty seaside town, gorgeous food. It is 500km from Paris though, so probably not a great option
- A mere 180 km away is Troyes which is deep in the Champagne region. Reims as well. I’ve never been but here it is another pretty place and of course the real deal Champagne. Apparently a good one to impress the ladies.
- Another option is to spend a day in Paris, then rent a car, then drive to the Normandy coast and spend 2-3 days exploring the beaches, food and the WW2 trail. finish the drive up in Calais and just to the UK that way.