Frankly, I never quite understood why Americans were raving about this café, whose decoration is over-kitsch, prices are outrageously high, and the waiters a caricature of Parisian "rudeness". Most of all, there won't be one single Frenchman/woman around, you'll be surrounded by tourists. But after all, it might be the Fodor's, upper-middle-class version of those travelers cafés you see in India or China, where backpackers exchange tips and used Lonely Planet guides !
This was not on our list of places to visit (due to its preponderance in all the tour guides, whereupon I decided it was probably "touristy"). But, I had read somewhere that the decor would render one in the midst of a Renoir painting, and we happened to be walking by, so gave it a try. Be advised that there are three dining areas (a sidewalk cafe, indoor cafe, and the main restaurant) each with its own menu. We had lunch in the main dining room. It wasn't inexpensive, but not outrageous either. It was one of the finest meals we enjoyed in Paris. I can still remember the wonderful food - a salad of endive with walnuts and gruyere and the finest (there was a fancy French name for it) chicken stew I've ever tasted. The latter was so beautiful prepared that the potatoes had been perfectly "carved". The bread was awesome. The rest rooms were spectacularly beautiful (have some coins with you).
The Cafe de la Paix is part of the Intercontinental Grand Hotel next to the old opera on Bd Capucines up from the Madeline. I think it gained it's fame about 100 years ago during the 1890's when the Opera and Belle Epoque era were in their peak. It is expensive and there is nothing special about their food. The outdoor sidewalk cafe is picturesque, but as pointed out in another reply it will be loaded with tourists and it will pretty much be nothing but other tourists walking by. I would not return to the Cafe and would not reccommend it to anyone, but personal tastes do vary.
There are so many inviting sidewalk cafes in Paris, I don't know that I'd try to find ONE. We had a delicious meal our first night in Paris, jet lagged, after a late afternoon walk around Notre Dame. It was a typical, neighborhood place on the right bank somewhere between city hall and Bastille. Don't think I could ever find it again. The waiter's English was as bad as my French, but he was charming, helpful, and our meal simply hit the spot. There was obviously a resident dog, mostly german shepard, who came over and laid his head in my husband's lap. Our plates were empty, but we fed him some leftover crusts of bread with the meager remains of gravy from our plates. He curled up on our feet while we finished our wine, and didn't move on to his next conquest until we paid the bill and left!
We LOVED this place. Gorgeous, fabulous food. And, it was half empty (at 3PM) and certainly not loaded with tourists (or a single canine patron). One of THE MOST BEAUTIFUL restaurants we experienced in all of Paris. We thought the prices were moderate (for Paris) and the food was delicious. On our list for next time.