Guys, it is easy. Just take the cityplan and find out where the Opera is. From the Place de l'Opera (easily reachable by metro) you go down Rue de la Paix toward Place Vendôme. You can find already something interesting between the Opera and Vendôme. up the big Place Vendôme there are good chances to find something, with the Ritz Hotel and so on. Once you are done, you keep going the direction you were following, you will soon reach a T junction. (an hotel before reaching it, on your right) You turn right, this is called Rue de Rivoli(actually to the left there should be another Hotel). Anyway, you turn right and walk untill the next square. this is the big Place de la concorde, hotel again, and lot of traffic -> many cars
you are now at the beginning of the Chmaps Elysées, but the first part is a bit quiet and you will be tired already
so you can take the metro toward the Arc du triomphe and get out at Franklon Roosevelt. You come back to the light and when facing the arc du triomphe (still far away), on your left you find Avenue Montaigne, full of boutiques, restaurants and hotels. walk down this road, this is mandatory. You walk untill you reach a pretty big junction and here you turn a tight right to enter Avenue George V, again mandatory you walk up this road untill you will come back to the Champs, and you just did a nice triangle. Now you keep walking toward the Arc du Triomphe, by paying attention to the traffic or parked cars. if you are really it you can also go under the Arc, come back exactly on the opposite side and go down Avenue de la Grande Armée, but you just did the most important part.
Basically last time I did that little tour at least twice a day
Do not forget the little side roads, always keep your eyes open