It's a bit of a cliche for a romantic celebration but its status as the city of love is justly deserved. We have been lucky enough to visit Paris a few times though not always together and usually with children. This trip was to celebrate our 10 year wedding anniversary ( 15 years together).
We stayed in Le Metropolitan having been seduced by this beautiful view of Paris.
I thought about writing a list of recommendations but this is covered comprehensively by Paris in four months here. (If you are planning a trip to Paris, I highly recommend getting lost in her feed). My biggest tip would be to learn some french phrases before you go. It makes such a difference. Parisians are usually more than helpful if they see you trying to use their language. A basic phrasebook will go a long way here.
Our favourite thing to do was just wander, take in the sights and stop when the fancy took us. This might be in response to our usual routine which is hectic and dictated by little children's needs. If it's a first visit for you, I'd recommend getting a two day city sight-seeing bus tour. It includes all the main tourist sights and you can jump on and off as and when the fancy takes you. It's a great way to get your bearings of the city and to get some behind the scenes information on some of the biggest tourist draws.
Paris architecture is so beautiful. Directly above is the facade to the sumptuous Paris opera house: Palais Garner. You can check out what performances are coming up here or indeed just book a general tour of this decadent building. Galleries Lafayette, one of the biggest shopping stores in Paris, is nearby if you want a shopping fix.
There are some great recommendations for food in Carin's article (Paris in four months) mentioned above but make sure and leave room for all the bread and delectable patisserie selections too.
If you get a chance, I'd highly recommend visiting Monet's waterlilies at the Musee Orangerie. I find that a lot of art escapes me but these paintings took my breath away. The Jardin des Tuileries outside the museum (sandwiched between the Louvre and Place de la Concorde are a great spot for people watching and crepe snacking pre or post visit.
Notre Dame as immortalised in The Hunchback of Notre Dame written by Victor Hugo who also wrote Les Miserables. It's free to visit with a fast moving security line. It is very popular with tourists but I'd still recommend a visit and if you are feeling fit, booking onto one of the tours that takes you to the top of the towers.
The Sacre Coeur is in the Montmartre district of Paris. There are some great views of the city from here and although several of the streets throng with tourists, there is always a quiet street/ viewpoint to be found with a little exploration.
Magical Eiffel dreams by night. Yes this is a massive tourist hub but i am one of the many happy sheep drawn to this tower. When it sparkles (on the hour every hour from dusk until midnight) it feels truly magical. On the trocadero, dance lessons take place until well into the night. I can't think of a better back drop to learn the tango to.