You can explore Paris for years, but a first visit works best planned by neighbourhood rather than by a list of sights. The banks of the Seine in the city centre are a UNESCO World Heritage Site.
Museums
The Louvre needs at least half a day and a timed ticket. The Musée d'Orsay has the Impressionists in a former railway station. The Centre Pompidou, the Rodin Museum and the Orangerie with Monet's Water Lilies are for the following days.
Neighbourhoods
The Marais has old mansions, galleries and boutiques. The Latin Quarter and Saint-Germain have bookshops, cafés and the Luxembourg Gardens. Montmartre is the hill with the Sacré-Cœur and a view over the city. Canal Saint-Martin has local bars and waterside walks.
The Eiffel Tower and the Seine
The tower is best seen from Trocadéro and from the embankments at sunset. A boat trip on the Seine is an easy way to see the centre in an hour.
Food and where to stay
Bistros, bakeries and cheese shops in every quarter. Hotels are in Where to stay, such as Le Bellune with its spa in the 15th arrondissement. Events are in Events.