From Louvre to Champs Elysees quite a distance, but still reachable by foot. Plus you won't be feeling tired as the whole junction fulled with branded store where you can shop like crazy.
First you will saw The Grand Palace (Le Grand Palais) and opposite of it Opera House (Petit Palais)
Very obvious this the largest LV store in Paris and is just next to Arc de Triomphe.
You can climb up the Arc but not free of course. You need to pay 9.50 euro to suffer.
Next, just take a Metro to Bir-Hakeim and you'll see Eiffel Tower from far away.
For Eiffel Tower, it is advisable to book the ticket online. Else you will just turn your back and gone home when you see the queue. Too bad too sad, even if you have the online ticket, you still need to queue as the elevator can only fill up 15-20 people at a time.
On the way to Trocadero for a Eiffel Tower Night Shot.
Wait until 9pm and there will be a spectacular light show.