Go to the outdoor markets!
They’re one of my favorite things about Paris. As a tourist, it’s possible to side-step them, but seek one out! There are close to 100 roving and street markets throughout the city, open every day except Mondays. Pick up a Pariscope at a street newsstand for a complete listing of days and times, or look here.
A few of the best roving marchés are Richard-Lenoir (Th. and Sun. 7 a.m.-3 p.m. at métro Richard-Lenoir in the 11è), Aligre (T-Sat. 8:30 a.m.-1 p.m. and 4-7:30, Sun. 8:30-1:30 p.m. near métro Ledru-Rollin in the 12è), and the one that I lived next to, Saxe/Breteuil (Th. and Sun. 7 a.m.-2 p.m., métro Ségur or Sèvres Lecourbe in the 15è). Markets are free to wander through, entertaining, and very French. Watch the venders engage with the customers; peruse primeurs (first fruits and vegetables of the season), the freshest eggs, cheese, meats, fish, and flowers, clothing, bric-a-brac and kitchenware; and be aware of little, old ladies whipping through the aisles with their rolling totes — they’re dauntless.
Go in the late morning and pick up a picnic lunch. You can find everything there — Normandy apples, Greek olives, cheese, baguettes, roasted chicken, chocolate tartes, wine — even sun hats and paring knives.
Street markets are also fun. My favorite is rue Mouffetard, the market street I did my field research project on during the semester. The produce there is expensive compared to other markets, but go for the Sunday morning ambiance alone. The music and dancing starts at 11 a.m., and lyric sheets are distributed so everyone can join in. One of my first Projo blogs was on this market street, and I came to love it more each time I went back, seeing the same faces each week and making friends. I watched a couple of tourists come over towards the music, and as they watched, big smiles spread across their faces.

Locals dance and sing along to the Mouffetard Musette behind the market every Sunday morning.
Have a picnic (pique-nique)
Enjoy a picnic (with your food from the morning's market) at one of Paris' many nice picnic spots. Pont Des Artes just in front of the Louvre is a popular place; it’s one of many Parisian bridges over the Seine that connecting the Right and Left Banks. This wooden footbridge, built in 1803, is popular among French young people as a picnic spot and place to relax with friends. In early May, my friend Chiara had a birthday celebration on the bridge and we had a picnic under the clear night sky, overlooking the Seine and a sparkling Eiffel tower. We brought blankets, wine, and cake, and sat comfortably on the bridge in the open air. There’s also the park near the Eiffel Tower, Champ de Mars (métro École Militaire on 8), and Jardin du Luxembourg (stop on RER B or walk from métro Cluny-La Sorbonne on 10). There’s also a nice garden at the métro Cluny-La Sorbonne next to the Cluny museum.
Eat nutella crêpes!
You can’t do Paris without a crêpe or two. Nutella is the best, but there are many options including sucre (sugar), citron (lemon), a selection of confitures (jams), Grand Marnier, and chocolate. Crêpe stands dot the more touristic areas of Paris, and it’s worth it to compare prices and also check to see if the crêpes are pre-made. For me, part of the fun of buying a crêpe is watching it be made — as the batter is poured onto the skillet and artfully raked into shape, then later flipped, the filling spread, and the crêpe folded before being handed over still steaming hot. I was always very skeptical of crêpe stands that had a mountain of pre-made crêpes, and when the customer ordered, it would just be filled, folded, and served, luke-warm. My favorite crêpe stand is tucked into the end of rue de la Harpe, just outside the Cluny-La Sorbonne métro (on the 10), next to McDonalds. They make delicious Nutella crêpes for 2,30 euros which is one of the better prices I found in Paris (they climb as high as 3,50 for just Nutella).
Take a coffee at a café

Cafe Panis, near Notre Dame
The Parisian café culture represents a different pace and lifestyle than what American are used to. Un café pour emporter (a coffee to go) is very rare in Paris. Part of the Parisian experience is enjoying, slowly, a cup of joe and people-watching from an outside table. Heed this warning though: check the prices before you order! I ordered and drank one cappuccino at a café at Bastille, and then looked at my bill for 7,50 euros! I learned my lesson. Café crèmes and cappuccinos usually cost around 4 euros each ($5) at tables, so a simple café (coffee) or my favorite, a noisette (hazelnut coffee) are better alternatives for about 2 euros each. For more authentic ambiance, order and drink your coffee at the bar where the prices are about half of what you would pay sitting at a table.
Most cafés have good, simple food at decent prices. At one of my favorites, Le Mouffetard (116 rue Mouffetard in the 5è, métro Place Monge), I had an excellent mozzarella and basil tartine with a fried egg. Look for the Croque Monsieur, one of Paris’ tastiest specialties, and standard café fare. It’s essentially a hot grilled-ham-and-cheese sandwich, but more filling and flavorful than the American counterpart. I always ordered mine sans jambon (without ham). Look for other versions, too, including Croque Madame, which is served with a fried egg.
Avoid tourist-trap restaurants on busy boulevards
As I traveled to London, the south of France, Italy, and Greece, this much held true: if you go a street or two behind the main thoroughfare, you will find authentic food at more reasonable prices. My best recommendation is to look for places off the busy boulevards like St. Michel and rue de Rivoli that serve mediocre food at jacked-up prices. Avoid the touristic rue de la Harpe at métro St. Michel! The pedestrian street is chock-full of souvenir shops, Greek restaurants, crêperies, and the like. It’s tempting because all the restaurateurs stand outside, doling out offers for free drinks. The street is charming for a wander-through, but everything’s over-priced and the food is low-quality.
Instead, head to the back of the Quartier Latin (in the 5è) or the Marais (in the 4è arrondissement). They're great areas to explore, with lots of cute restaurants, while still staying central in the city. I ate at a good, quiet place called Jardin du Marais (corner of rue Vieille du Temple & rue du Roi de Sicile) in February. My friend and I got there around 7:30 p.m. and we were the only diners at that “early” hour (The French don't eat dinner until 8 p.m. or much later). I opted for the fixed-price menu and ordered avocat vinaigrette et salade (green salad with avocado), Pizza Reine (with ham and mushrooms, but I asked for no ham), and mousse chocolat for around 11 euros. Also, wherever you eat, always ask for a carafe d'eau, a free pitcher of tap water, if you don't want to buy still or bubbly bottled water. While visiting Italy and Greece this month, I missed Paris' free tap water.
One of my favorite little places is close by in the Marais, the popular L’As du Fallafel (34 rue des Rosiers, between Hôtel de Ville and St. Paul métros. Follow rue des Ecouffies a couple blocks behind Rivoli). There’s seating inside, but I preferred to order a vegetarian fallafel sandwich pour emporter (to go) from the window and watch the master prepare the Middle-Eastern specialty, stuffing a pita with falafel, Turkish salad, eggplant, cabbage, hummus, and tahini. It’s a quick and cheap lunch for just 4 euros, and an easy walk along rue des Rosiers to the pretty Place des Vogues. While you're there, explore the medieval streets. The interesting Musée Carnavalet is just down the street (23, rue de Sévigné), as is the Picasso museum.
Last thing — enjoy the inexpensive, amazing bread from bakeries (boulangeries). You can get a baguette at any boulangerie for about 75 centimes ($0.95), and a demi-baguette (half) for around 40 centimes, or a flûte, or my favorite — the banettes. And, indulge in desserts from pastry shops (pâtisseries). They're amazing. I miss them.