Sacre Coeur is worth a visit and you can pay to go up the towers inside and you get some great views of Paris.
This may not be relevant, but it surprised me. You can't fly to Paris from Gatwick!
So either Heathrow or Eurostar (via St Pancras or Ashford)
Did I not hear on the radio that there is a daily flight from Shoreham
And it's supposed to be romantic.
Thanks all. I don't think a weekend is going to be enough looking at the replies!
If you want romance you've picked the right place. A romantic jesture that the good lady wife loved was writing our names on a padlock attaching it to the railings on the Solferino footbridge and lozing the key in The Seine.
As some have said, just walking around is the best way to get to know a big city. People who make a dash for the Metro all the time don't realise how close together many of the sights are. I do the same every time in London as well - the Underground distorts distances and makes you psychologically think the centre is bigger than it actually is.