Buying Stuff
Paris is a commodity fetisher's dream, and you can buy stuff anywhere. If you're shopping for particular things, though, certain areas of town are better than others.
For example, inexpensive youth-oriented clothes and shoes are
concentrated on and around the boulevard St. 
Michel
in the Latin Quarter. Leather jackets, especially during the sales
season, can be especially good deals. (Sale season, by the way, is
officially—really!—the month of July, when everything is marked down,
often drastically, to clear space for the fall lineups; look for the
word soldes plastered in giant letters everywhere.) Regarding
shoes, however, be forewarned: French shoes are unreasonably
expensive, so no matter where you look for shoes they'll no doubt seem
more expensive than they should be. Some of the larger stores like Eram
have a decent selection at reasonable prices, but if you're looking
for something uniquely French, you're going to pay for it.
You want luxury items? Head for the Place Vendôme and the Avenue Montaigne. (Metro Tuileries or Pyramides for Place Vendôme; Franklin-Roosevelt for Avenue Montaigne.) Expensive. Really. Just shopping for clothes and personal items in general? Well, you have to know about the grands magasins, the big department stores (grands magasins) in the 9th arrondissement. Galeries Lafayette, at 40 boulevard Haussmann, and Printemps, at 64 boulevard Haussman, will keep you busy for days (both are at metro Havre-Caumartin). These are giant stores, several buildings each, and they're jammed with merchandise and customers. The sidewalks in front of them are crammed with passers-by and with salespeople demonstrating odd or unusual kitchen products, somewhat reminiscent of what you'd see at a county fair. These are the places for some of the latest fashions at more reasonable prices than you'll find at the designer shops (although they're not cheap).
(By
the way, did you know that you've never had a cup of hot chocolate?
You haven't, unless you've had the hot chocolate "l'Africain"
(accompanied by some pastries) at the insanely good Angelina
on the first (French) floor of the Galeries Lafayette main building
(and make sure to look at the breathtaking dome as well). I don't know
how to describe the stuff: it's the most chocolaty liquid I've ever
encountered (and I've encountered more than my share…), and it's got a
density and a luscious thickness that are impossible to fathom. You
can order it by the pitcher, and truth be told, that's not enough. I
wish I could figure out how they make this stuff.)
La Samaritaine, at 9, rue de la Monnaie in the 1st (metro Pont Neuf) is worth a visit. This bohemoth of a department store is a tribute to elegance. It was founded in 1870, and in some ways it's the grande dame of Paris shopping. Before it closed for safety reasons in 2005 people knew it for its focus on luxury brands and for its rooftop restaurant. The store changed hands and was renovated, opening up again in 2021. In its current configuration it's more than a store—I think they're going for some new kind of luxury shopping experience.
There's also the Bon Marché. "Bon Marché" means cheap, which this place isn't. It's at 24, rue de Sèvres, metro Sèvres-Babylone. This place has all your upscale items under one roof, it's way less crowded and frantic than the grands magasins, and if anything just a little more chic. I've seen celebrities here, actually. Once you're in this area, you can head over to two other good shopping districts: Saint Germain/Saint Sulpice, and Rennes (just walk down the little rue Saint Placide to the rue de Vaugirard and the rue de Rennes).
Sale season is officially the month of July, when everything is marked down drastically. Look for the word 'soldes' plastered in giant letters everywhere.My favorite areas are the rue de Rennes and the surrounding streets, and the area around the Place St. Sulpice (where, by the way, one of the grandes dames of French cinema lives, but I won't tell you who or in which building—just keep your eye out). Saint Sulpice is also the church that figures prominently in The Davinci Code, but it's worth seeing anyway (ha!). The marquis de Sade was baptized there, as was the best poet in the world, Charles Baudelaire. There's a strange and unusual Egyptian obelisk in the church. Go inside—really—and you'll be glad you did. There's an Yves Saint-Laurent shop here that's especially amusing because the staff haven't yet been apprised of the fact that no one cares about snooty designer attitude anymore. Go in and they'll sniff at you and prance around, looking like one of those Saturday Night Live parodies of teenagers working at the Gap.
Music and books galore inhabit the FNAC
(and no one in the world knows what that stands for, by the way, but
it is la FNAC, so I'm guessing the first word is Fédération,
or something like that—[A Tom's Guide Mystery solved! A
reader—actually it took two readers to get this through my head
(thanks, Jan)—points out that not only is the first word, in fact,
Fédération, but that the whole 
thing
is Fédération Nationale d'Achat des cadres—thanks!]), and there are
two principal locations: in the sickening Forum
des Halles (metro Les Halles), where you have to go
underground on this scary and too long escalator ride which is made
even worse by the wan and destitute looks on the faces of the people
opposite you coming back up, making you wonder why you ever embarked
on this journey in the first place; and at 136 rue de Rennes,
not far from the tour Montparnasse (metro
Montparnasse-Bienvenue or Saint-Placide). Although the latter store is
more attractive and more pleasant to shop in, alas! the former store
seems to have a wider selection. They have tons of books on every
conceivable subject (and they're especially good on travel, comic
books [bandes dessinées], philosophy, literature, and art),
and they have a significant selection of books in English. The music
section is a dream come true, and the music is laid out by category in
a way that actually makes sense, and each department ("électronique,"
"variétés françaises‚" etc.) has a little info desk where you can
inquire about a particular CD or DVD, and the folks who work there
know everything and will actually help you. The best English book
store in Paris is not the one you think (that is, the one everyone
knows about, and hence deserves no mention here). Actually, it's
called the Abbey
Bookshop, and it's at 29 rue de la Parcheminerie, in
the 5th (in the little pedestrian streets off of St. Michel). They
have new and used books here in most conceivable subjects, all at
reasonable prices. Another favorite, over near the Bastille,
is La Manœuvre, at 58, rue de la Roquette (metro
Bastille). It's got a terrific selection of books (mostly in French,
with some English), and the space is terrific and invites serious
browsing. The staff are friendly and unusually knowledgeable. Tom's
Guide readers will likely also appreciate L'écume
des pages, located at 174, blvd Saint-Germain (metro
Saint-Germain-des-Prés). This place has some serious literature,
history, criticism, and other genres, but it also has good kids'
books, travel, and other quotidian subject matters. There are a lot of
other bookstores, of course. Tom's favorite place to go book-shopping
is on the Rue des Ecoles in the 5th arrondissement.
Here you'll find a dozen or so small- to medium-sized bookstores, some
specializing in a particular range of disciplines and others just a
sort of mishmash of stuff. Many of them have second-hand books for
those seeking a bargain. Unfortunately for you anglophones out there,
these are all pretty much exclusively in French. Finally, if you're a
college student, go to Gibert
Jeune, at the bottom of St. Michel and also up the
hill a little ways, because that's where college students are supposed
to go, and they do. It's got books, notebooks, and all sorts of other
things you didn't know you needed but which generations of college
students have discovered they've been lacking. I won't buy notebooks
anyplace else.
If you want to buy wine or other sorts of spirits and you have no idea what you're doing, go to a specialty shop. The big chain is called Nicolas, and they're all over, but you might also want to go to a mom and pop variety. These people know what they're talking about, and won't try to pressure you to make you buy things that are more expensive and out of your league. There are especially nice and helpful ones on the Ile St. Louis, right in the middle of the rue St. Louis en l'Île, and another at 13, rue Buci in the 6th, both of which are in areas you might find yourself walking around in anyway.
Now this is only for some of you, but if you're of those who believe
that chocolate is a near sacred substance that should be prized as
much as platinum—that is, if you have
an ounce of sense in your head—then run over right now to Debauve
et Gallais at 30, Rue des Saints-Pères in the 7th
arrondissement (but almost the 6th: 01 45 48 54 67, metro
Saint-Germain des Prés or Sèvres-Babylone). You will swoon as you
enter the storefront (which is classified as a historical monument),
and you will become drunk with chocolate lust as you contemplate the
displays laid out before you. This establishment has been around since
1800, when Sulpice Debauve, who had been pharmacist to Louis XVI
(guess that didn't work out so well) not far from the current
location. You can buy a ton or a single piece. I once asked them for
the richest piece they had and they gave me a bite-sized piece that
was so dense I actually couldn't finish it.
Grocery stores aren't anywhere near as big or as numerous as they are
in the U.S. Look for Inno, Franprix,
or Monoprix, chains of supermarchés (but the really
big ones are called hypermarchés, which makes me conjure up a very
amusing image). Most of these stores are somewhat cramped and
impersonal, and the change
crisis continues even after the adoption of the euro. You'll
have to bag your own groceries—and, indeed, bring your own bags—but
you'll find whatever you want here (including spirits). If you're a
food snob and you want really fine foods, check out either Hédiard
or Fauchon,
both on the Place Madeleine (metro Madeleine).
You'll find all sorts of wild things here (including peanut butter!),
and the staff is attentive and knowledgeable. I once worked at the
Hédiard in the sixteenth arrondissement (but sadly it's no longer
there, and there's not even a plaque commemorating my service on that
spot), and I was very attentive and knowledgeable. If you want to get
someone an interesting food gift, try the pâtes de fruit at
Hédiard: they're a more 
sophisticated
version of those jelly candies coated with coarse sugar you got in the
movie theaters when you were a kid, but these come in a variety of
adult flavors, including bitter orange and blackberry, and you can
have them packed in attractive gift boxes. They're strangely
addictive.
BTW, since I just mentioned it, if you want something gift-wrapped, you tell the salesperson that it's "pour offrir" (literally, "to offer").
Like to shop around for junk, in search of that amazing find—whether a Persian rug, a Renaissance-era dining table, or a vintage 1950's ashtray? Then you have to see the marché aux puces de Saint-Ouen. A marché aux puces is a flea market, and this one's absolutely huge, with an absolutely enormous variety of stuff. Take the metro out to Porte de Clignancourt and follow the crowd down the street. Then browse something live 2000 different booths, some indoor, some outside. The market is open Saturday, Sunday and Monday, from early morning until late afternoon-early evening. This thing has been around for over 100 years, and you might be put off at first by the throngs of people there, but it's worth it to see all this stuff. (Do watch your wallet or bag, though; this place has some operators.) There are also some pretty decent restaurants and cafés in the area surrounding the market (mostly to the north and east), so you can even make a day of it—but only on Saturday, Sunday, and Monday, from 10:30 until 6:00.
Les
bouqinistes are booksellers who have these green stalls
built in along the walls looking over the Seine. Generally speaking
they have a lot of old books and magazines, and you're unlikely to
come across any rare first editions or anything (these people aren't
idiots—they know what they're selling), but you might find the odd
interesting old print or whatever. The thing about the bouquinistes is
that even if you don't find anything interesting to buy, it's really
fun to shop here.
A lot of people are intimidated about looking at or—gasp!!—trying on clothes in Parisian boutiques. Well, don't be. Well, wait—be, but learn how not to be. Although this is less the case than it used to be, a lot of salespeople in clothing stores (and I'm not really talking about the big department stores here) can still be a little high pressure. So what? There's a little drama that might play out, and as long as you play the role you're supposed to play, instead of the one a pushy salesperson might want you to play, you're fine. They'll want you to feel bad for trying something on and not buying it. If some wise acre tries to pull this on you, you trump them by acting offended that he or she would even think of selling you something of such inferior quality, and that you're lucky to have noticed, at just the last minute the defects the merchandise sports. Always maintain the moral high ground if someone tries to pull this crap on you (although it's unlikely). The bottom line here: don't be afraid to try things on even in the smallest, trendiest boutique. Just be armed (and now you are) with all the cultural weaponry required.
Speaking of buying clothes, there used to be—and as far as I can tell it's gone—at least one vending machine for buying... blue jeans. It was the weirdest thing I ever saw, and it was this big sucker right in the middle of the giant Auber RER station. It was bigger than a photomaton (those booths you can get your picture taken in), and you'd stand inside it, pull this sort of cord thing around your waist to determine your size, insert your credit card, and out would come a pair of blue jeans. I couldn't ever figure this out: was this in case you accidentally left the house without wearing any pants?