While planning my trip to Paris, as an American historian I thought it would be fun to visit sites dealing with WWI and WWII. What I came to find out was that the city was relatively spared from the Wars, in terms of physical damage and battles, so there are really no major sites to visit.
In 1914, when German forces raced into France the French government through everything they had at the German advance and stopped them outside the cite on the Marne River. The city even requisitioned all the city taxi cabs to rush volunteers to the front. Parisians suffered during the war, but the city itself was not hurt as it mostly served as a backdrop behind enemy lines and a place for the wounded. This was the first war with long range artillery and Paris did take some hits from enemy fire, especially the Saint-Gervais Church, but came out of the war relatively unscathed.
In 1940, when again the Germany army rolled into France, this time they were faster and more powerful, and the French government fled the city allowing the Nazis to occupy the city with little damage. Germany would control Paris for the next four years until 1944 with the Allied invasion of Normandy. With the Allied advance, the Germans pulled out of Paris. They were ordered to destroy the city, but the German commanders ignored the orders and retreated.
Whereas so many European cities suffered sever damage during the two great wars, Paris and its beauty were spared. This does not leave many battle sites to visit in the city itself, but it does leave me a beautiful city to enjoy with plenty of other historical periods to discover. This is the view out my hotel window and of course we had to visit the Eiffel Tower on our first night.