I was born, then lived in, Paris until I finished my studies. I know the city fairly well even if I need to check the métro map all the time as I have forgotten where the connections are. Not much has changed since I left, but at the same time many things have. It's hard to explain. Some parts of town seem to be exclusively designed for tourists, but maybe I notice this only because now I am nothing but a tourist in my home town. Starbucks are everywhere, as are the Amorino ice-cream shops, but there are still thousands of bakeries. What once was a low-profile flea market near where my grandmother used to live is now an outrageously priced antique-oriented market for Japanese tourists.
Anyway, for what it's worth, here are a few of the things I like to do in Paris.
This time we took a hotel in my old neighbourhood Montparnasse. It was the best hotel I've been to in Paris in that price range so if you need the name, let me know. A visit to Montparnasse isn't complete without a meal at Chez Josselin (67 rue du Montparnasse 14°), the ultimate crêperie in town. I used to go there as a child with my parents already. Even in Bretagne I haven't eaten so well. The decor is kitschy and it's very small and very busy but well worth the wait, and please never go to any of the other crêperies in the same street, nothing compares.
Montparnasse itself is a bit soulless these days. But for a villagey feel, find the Rue Raymond Losserand (Métro Gaîté), it is a quiet, pretty much tourist-free zone with restaurants and bars, and nice bookshops. The Boulevard Pasteur has perked up a bit and you'll find many French restaurants once you go down from the Place de Catalogne. If you're looking for something a bit more alternative than your typical brasserie, turn into Rue Falguière and go to Aux Artistes and then a bit farther down the street to Le Bréguet for a beer.
Of course, you won't be too far from the Luxembourg Garden, which is Paris' answer to Central Park.
Then you can come out the other side and go down the Boul'Mich (Bvd St Michel), see Notre-Dame and go all the way to Châtelet and les Halles. There you can choose to buy 3 kilo of Valrhona chocolate pastilles at G.Detou (rue Tiquetonne) at wholesale prices or not. But definitely have a happy hour drink in the Montorgueil area.
Mmmhhh mango mojito! Makes you appreciate being childless for a few days...